Journals >Acta Photonica Sinica
Contents
2014
Volume: 43 Issue 8
37 Article(s)
Export citation format
Research Article
A Method of Sparse Optical Grooming with the Smallest Cost and Largest Degree
LIU Huan-lin, XU Yi-fan, FANG Qiang, and CHEN Yong
Grooming can increase multicast traffic request sucessful transmission probability and improve fiber link bandwidth utilization. But it certainly increases the network cost and complexity that all nodes are configured as grooming node in WDM network. Grooming node selection strategy was studied in the sparse grooming nGrooming can increase multicast traffic request sucessful transmission probability and improve fiber link bandwidth utilization. But it certainly increases the network cost and complexity that all nodes are configured as grooming node in WDM network. Grooming node selection strategy was studied in the sparse grooming network. A grooming node selection strategy based on smallest cost largest degree was proposed. According to difference of grooming node function and non-grooming node function, the sparse grooming transmission method was improved to transmit the request for multicast request in the sparse grooming network. Lastly, according to the network′s blocking probability limit, a sparse routing method, integrated the node selection strategy with the smallest cost largest degree and multcast traffic grooming transmission method,was put forward to meet the multicat request with minimal grooming nodes. The simulation results show that the proposed strategy method can save number of grooming required nodes, optimize the location of grooming nodes and decrease the network node construction cost when network has given number of wavelengths per fiber and given transceivers of node in the sparse grooming network..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 43, Issue 8, 806001 (2014)
Fuzzy Variable Structure Multiple-model Tracking for Airborne Laser Communication System
CAO Yang, RONG Jian, ZHANG Hong-min, WANG Pei-rong, BAO ming, and GUO Jin
High precision tracking system for airborne laser communication is usual to adopt multiple models algorithm with a fixed structure,which brings about unnecessary inter-competition among the amount of models and calculation burden.In order to resolve this problem,variable structure multiple-Model based on digraph switchHigh precision tracking system for airborne laser communication is usual to adopt multiple models algorithm with a fixed structure,which brings about unnecessary inter-competition among the amount of models and calculation burden.In order to resolve this problem,variable structure multiple-Model based on digraph switching and fuzzy inference was presented,graph switching rule and complete model set were established,the fuzzy inference mechanism was introduced to get matched degree for each filtering,the calculation complexity was decreased obviously.The Kernel particle Filter can move particles toward the posterior,root mean squared error between estimated and true model is minimum,the method could be introduced into fuzzy VSMM framework.Simulation results show that the algorithm improves the accuracy of tracking by reducing the competition of the models as well as reducing the computation burden..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 43, Issue 8, 806002 (2014)
Polarization Ytterbium-doped Fiber Laser Based on 45° Tilted Fiber Grating
FU Sheng-gui, LIU Xiao-juan, WEI Gong-xiang, GUO Li-ping, and GE Xiao-lu
The working mechanism and Polarization Dependent Loss (PDL) characteristics of 45° tilted fiber gratings working at 1 064 nm band were researched theoretically and experimentally. The 45° tilted fiber grating was fabricated in photosensitive fiber by UV-inscription technique. A phase mask with a period of 1 0The working mechanism and Polarization Dependent Loss (PDL) characteristics of 45° tilted fiber gratings working at 1 064 nm band were researched theoretically and experimentally. The 45° tilted fiber grating was fabricated in photosensitive fiber by UV-inscription technique. A phase mask with a period of 1 070 nm was rotated 33° to the fiber axis to produce tilted fringes of 45° in the fiber core. The length of the 45° tilted fiber grating was about 12 mm. The PDL value was about 7 dB over 1 040 nm to 1 085 nm. According to theoretical analysis, the main causes of the low PDL value was due to the unsuitable pitch and insufficient length of the phase mask. Using the 45°tilted fiber grating as a polarization selective device, a polarized Yb-doped fiber laser was demonstrated. The polarization extinction ratio of the output laser was more than 30 dB. The maximum output power of the fiber laser was 8.7 mW and the center wavelength was 1 065.4 nm with 3 dB line width of 0.08 nm, which can be stable after a long time work..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 43, Issue 8, 806003 (2014)
Cost-Efficient Approach Based on Connection Availability for Planning of Survivable Long-Reach Passive Optical Network
LIU Ye-jun, GUO Lei, YU Yin-peng, LI Bing, JIANG Pei-pei, and DAI Cui-qin
Focusing on the survivability of long-reach passive optical network against single shared-risk link group failure, a cost-efficient planning approach based on connection availability was proposed. First, a connection availability model based on failure probability was designed to estimate the connection availability ofFocusing on the survivability of long-reach passive optical network against single shared-risk link group failure, a cost-efficient planning approach based on connection availability was proposed. First, a connection availability model based on failure probability was designed to estimate the connection availability of each optical network unit. Each primary optical network unit not satisfying the connection availability requirement would be allocated some backup optical network units, each of which needed to reserve the backup capacity for the primary optical network unit. Then, deployed the backup fibers among different optical network units to establish at least one backup-optical-path between each pair of primary and backup optical network units. Through the computational simulation, the performance of proposed approach in deployment cost of backup fibers was analyzed. Results show that the proposed approach can achieve much lower deployment cost than the previous neighbor protection approach. The proposed approach would solve the problem of the joint optimization of backup capacity allocation and backup fibers deployment. The objective was to fully protect all traffic demand in the network by the minimum deployment cost of backup fibers, while guaranteeing the connection availability requirement..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 43, Issue 8, 806004 (2014)
Polarization Control in Long-distance Distributed Sensing System Based on STM32 Genetic Algorithm
LIU Hai-feng, TAO Jun-hao, ZHANG Ning, LIU Bo, and WANG Hu
Based on the STM32-microprocessor-manipulated,the polarization degradation in a 50 km long distance distributed fiber vibration sensing system was suppressed by using polarization controller in combination with the genetic algorithm.By exploiting the hardware features of STM32 and PCD-M02 polarization control module,reBased on the STM32-microprocessor-manipulated,the polarization degradation in a 50 km long distance distributed fiber vibration sensing system was suppressed by using polarization controller in combination with the genetic algorithm.By exploiting the hardware features of STM32 and PCD-M02 polarization control module,related genetic algorithm parameters were optimized to achieve the genetic-algorithm-based polarization control.Experimental results indicate that the approximately public optimal solution could be found by using the STM32-microprocessor-based genetic algorithm in a short time frame,and ultimately to effectively realize polarization control functionality.Our proposed polarization control scheme could be applied in the long distance fiber sensing system that highly requires the real-time as well as integration features..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 43, Issue 8, 806005 (2014)
Phase Demodulation of Single Closed Interferogram Based on Fourier Transform
XU Jian-cheng, and CHEN Zhao
An effective demodulation of single closed interferogram was proposed. The initial phase of the closed interferogram was estimated by using of Fourier transform, band pass filtering and inverse Fourier transform. Then the phase was obtained accurately by image segmentation, sign correction and Zernike polynomial fittinAn effective demodulation of single closed interferogram was proposed. The initial phase of the closed interferogram was estimated by using of Fourier transform, band pass filtering and inverse Fourier transform. Then the phase was obtained accurately by image segmentation, sign correction and Zernike polynomial fitting. Image segmentation and sign correction solve the problem of phase ambiguity, and Zernike polynomial fitting reduces the local phase error near the segmentation line . The qualitative relation between the residual phase error and the parameters of interferogram were analyzed by simulation, such as tilt, defocus and noise. Experimental result shows that the extracted phase by the proposed method is in good agreement with that tested by the ZYGO phase-shift interferometer and the residual phase error is less than one tenth of the reference phase. Numerical simulation demonstrates the effectiveness of this method..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 43, Issue 8, 810001 (2014)
Based on Texture Feature and Extend Morphological Profile Fusion for Hyperspectral Image Classification
WANG Zeng-mao, DU Bo, ZHANG Liang-pei, and ZHANG Le-fei
Single spatial feature is used in the traditional spectral and spatial feature fusion,which does not make full use of the advantage of high spectral and spatial resolution.In order to overcome the shortage,a method based on texture feature and extend morphological profile fusion for hyperspectral image classification wSingle spatial feature is used in the traditional spectral and spatial feature fusion,which does not make full use of the advantage of high spectral and spatial resolution.In order to overcome the shortage,a method based on texture feature and extend morphological profile fusion for hyperspectral image classification was proposed.Firstly,with the principle component analysis,the hyperspectral image dimension was reduced and the spatial correlation was eliminated,then using the gray level co-occurrence matrix the texture features for each principle component were extracted and the extend texture features were got,lastly combined the extend morphological profile and part spectral features hyperspectral image is classified.The experiments show that the proposed method can overcome the limitation of traditional spectral feature classification and improve the accuracy of hyperspectral images classification..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 43, Issue 8, 810002 (2014)
Real-time Compressive Tracking Method Based on Phase Congruency
ZHANG Lei, WANG Yan-jie, and HE Shu-wen
The target tracking algorithm based on compressive sensing can cause the instability or failure in the tracking process when the illumination changes drastically.To deal with such problem , a developed tracking algorithm based on phase congruency was proposed,which is insensitive to the illumination.The phase congruencThe target tracking algorithm based on compressive sensing can cause the instability or failure in the tracking process when the illumination changes drastically.To deal with such problem , a developed tracking algorithm based on phase congruency was proposed,which is insensitive to the illumination.The phase congruency transformation of the image in the search area is calculated firstly, then the features extracted from the transformed image are used in the classifier to determine the target′s location.Experimental results show that the proposed method has a strong adaptability when the target has a drastic variation in the illumination, and the average frame rate can reach 22 fps when the target size is 50 pixel×55 pixel.Compared with the tracking algorithm based on compressive sensing, the proposed algorithm still has a very good robustness to the drastic variation of the target′s illumination.Besides, to a certain extent, the tracking is also stable to scale and textures change..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 43, Issue 8, 810003 (2014)
Near Infrared Scene Simulation Based on Reflectance of Typical Target
JIANG Le, BAI Ting-zhu, DING Yan, and ZHOU Qiang
An algorithm to inverse near infrared images based on visible light images and reflectance of typical target was proposed, according to the relationship between digital number of near infrared images and digital number of visible light images and reflectance of typical targets. In order to gain its relationship, two exAn algorithm to inverse near infrared images based on visible light images and reflectance of typical target was proposed, according to the relationship between digital number of near infrared images and digital number of visible light images and reflectance of typical targets. In order to gain its relationship, two experiments were carried out. Firstly, radiometric calibration of camera in visible and near infrared waveband (0.38~1.1 μm) was conducted by using integrating sphere; secondly, visible light images and near infrared images of some typical targets were obtained by the camera; at the same time, the spectral reflectance which ranges from 0.38 μm to 1.1 μm for those typical targets was obtained by spectrometer under the same weather conditions. The atmospheric transmittance was also considered. The inversion result shows that the proposed algorithm can better reflect the characteristics of typical target in near infrared waveband, and this work lays a solid foundation to achieve the near infrared scene simulation..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 43, Issue 8, 810004 (2014)
Inverse Modeling of Mirror Surface Figure Based on Finite Element Contact Analysis
LIU Yong-ming, XIE Jun, TIAN Wei, SUI Yong-xin, and LIU Zhen-yu
In order to inversed compute the optical element surface profile using the finite element method and the surface shape interference test results, the composition of interference test results was decomposed, and the testing principles of the rotational averaging method were analysised. The feasibility of using simplifieIn order to inversed compute the optical element surface profile using the finite element method and the surface shape interference test results, the composition of interference test results was decomposed, and the testing principles of the rotational averaging method were analysised. The feasibility of using simplified geometrical model to caculate the deformation of an optical element with arbitrary given surface shape was discussed. Surface profile inversion model was proposed based on finite element method. A finite element analysis model was then presented based on surface-surface contact modeling. A plane mirror supported by three rigid spheres as the simulation and experimental model, the rotationally asymmetrical surface deviation was quantitative analysis using the numerical method presented in this paper and the N-step rotational averaging method. The obtained results show that the root mean square of rotationally asymmetric surface is 2.933 nm obtained through numerical method and the root mean square of rotationally asymmetric surface is 2.75 nm obtained through N-step rotational averaging method. Subtracted result of the two rotationally saymmetric surface show that the root mean square of the subtraction are 6.31% of the numerical method result and 6.73% of the N-step rotational averaging method result. Finally, comparing the optical element surface profile computed by proposed inversion model with the surface profile tested by N-step rotational averaging method. Results show that the root mean square of optical element surface profile are 3.535 nm and 3.351 nm respectively. Subtracted result of the two surface profile show that the root mean square of the subtraction are 11.67% of the inversiong result and 11.06% of the result tested by N-step rotational averaging method .The proposed inversion model is accurate and reliable..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 43, Issue 8, 812001 (2014)
Alignment of the Space Optics Using Discrete Light Source
Zhang Xiaoming, Chen Hongbin, Wang Jihong, Qi Bo, and Shi Jianliang
In order to solve the problems of aligning the space optics by wavefront errors or stellar image, the large amount of calculation and the great influence of surface shape errors, and so on, a discrete light source is proposed. And based it on, an alignment and measurement optical system is designed. The optical system In order to solve the problems of aligning the space optics by wavefront errors or stellar image, the large amount of calculation and the great influence of surface shape errors, and so on, a discrete light source is proposed. And based it on, an alignment and measurement optical system is designed. The optical system is designed to measure and align a Ritchey Chretien telescope quickly by using the discrete light source as the reference ray. When the parameters of the optical system have been known, the relationship could be established exactly between the alignment errors and the spot diagram on the image plane. A simulation flat form is developed by using of the optical design software and the mathematics calculation tool. Then, the algorithm is proved in the simulation flat form. The simulation results show that using the discrete light source could reduce the amount of calculation, decrease the effects of the mirror errors and the stray light and have the precise calculation result..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 43, Issue 8, 812002 (2014)
The Statistical Properties of Dynamic Speckle Produced by Rotating Rough Target
YANG Zhi-qiang, WU Zhen-sen, ZHANG Geng, and GONG Lei
The dynamic properties of rotating symmetrical targets with visible band laser are analyzed and the time sequence speckle optical system to measure multi-pose rotating targets is designed,with the aim at the characteristics recognition of line-of-sight angle and angular velocity for rotating targets,on the basis of theThe dynamic properties of rotating symmetrical targets with visible band laser are analyzed and the time sequence speckle optical system to measure multi-pose rotating targets is designed,with the aim at the characteristics recognition of line-of-sight angle and angular velocity for rotating targets,on the basis of the laser scattering theory.The results reveal that the curve of normalized time correlation function can be achieved by adopting multi-map time correlation function algorithm,for dynamic speckles at different line-of-sight angles and angular speeds; the relationship is obtained of time statistical properties with line-of-sight angle within 20°-90° and angular speed within 0.5r/min-6r/min..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 43, Issue 8, 812003 (2014)
The Surface Characteristics of Diamond Wire Sawn Multicrystalline Silicon Wafers and Their Acidic Texturization
LIU Xiao-mei, LI Miao, CHEN Wen-hao, and ZHOU Lang
In order to solve the incompatibility problems between the diamond cut multicrystalline silicon wafer and the currently used HNO3-rich HF-HNO3-H2O acidic wet etching technology, the surface feature of diamond cut multicrystalline silicon wafers was investigated, and the acidic etching was revealed aimed to improve the In order to solve the incompatibility problems between the diamond cut multicrystalline silicon wafer and the currently used HNO3-rich HF-HNO3-H2O acidic wet etching technology, the surface feature of diamond cut multicrystalline silicon wafers was investigated, and the acidic etching was revealed aimed to improve the acidic texture of diamond cut multicrystalline silicon wafers by greatly increase the proportion of HF in the mixed acid solution. The results show that, diamond cut silicon surfaces have about 33% smooth band areas, with the rest of surface being pits of cracking and spalling, similar to the surfaces of slurry cut silicon wafers. These smooth areas leads to 3%~4% higher light reflectivity as compared to the slurry cut multicrystalline silicon wafers. The smooth area is relatively difficult to etch in both HNO3-rich and HF-rich HF-HNO3-H2O mixed acid solution, making the light reflectivity reduction 1%~2% lower than the slurry cut wafers, after the acidic etching. The final light reflectivity of the acidic wet textured diamond cut multicrystalline silicon wafers is thus 4%~6% higher than the similarly textured slurry cut multicrystalline silicon wafers, which is not low enough for solar cell application. Both HNO3-rich and HF-rich etching systerm, can not solve the problem of etching diamond wire saw multicrystalline silicon wafers..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 43, Issue 8, 816001 (2014)
The First-Principles Study of Electronic and Optical Properties of Co-Cr Co-doped Rutile TiO2
YANG Zhi-huai, ZHANG Yun-peng, KANG Cui-ping, ZHANG Rong, and ZHANG Mei-guang
Based on the density functional theory, using the first principles pseudopotential plane wave method to calculate Co, Cr doped and Co, Cr Co doped rutile TiO2 band structure, density of States and optical properties. The results show that: the band gap of pure rutile is 3.00 eV, Co doped rutile TiO2 band gap of 1.21 eVBased on the density functional theory, using the first principles pseudopotential plane wave method to calculate Co, Cr doped and Co, Cr Co doped rutile TiO2 band structure, density of States and optical properties. The results show that: the band gap of pure rutile is 3.00 eV, Co doped rutile TiO2 band gap of 1.21 eV, the conduction band and valence band top bottom are located in the G spot, is a direct band gap between the valence and conduction band, the impurity level by Co 3d and Ti 3d hybridization; Cr doped rutile TiO2 direct band gap of 0.85 eV, the impurity levels between the valence and conduction band by Cr 3d and Ti 3D orbital track structure, the conduction and valence bands are moving toward low level direction, Also, it is doping modification of ion selective basis; Due to the strong hybrid electron, make the O-2p state and the Ti-3d state to the Co-3d state and Cr-3d mobile of Co-Cr Co-doped, the valence band energy shifts to a higher energy level and the bottom of the conduction band energy level shift to lower energy, so greatly reducing the band gap width. The dielectric peak doped rutile TiO2, refractive index and absorption coefficient all shift to lower energy; In the range of E<2.029 eV, pure rutile imaginary part of dielectric function, k and absorption coefficient is zero, the transition strength after doping is higher than the transition intensity of undoped zno, Transition intensity of Co, Cr Co-doped is greater than Co doped and Cr doped, Co, Cr Co-doped can strengthen the electron optical transitions in the low end, visible light catalytic performance has better..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 43, Issue 8, 816002 (2014)
Electronic Structure and Optical Properties of Orthorhombic P-doped Ca2Si Calculated by the First-principles
CEN Wei-fu, YANG Yin-ye, FAN Meng-hui, and SHAO Shu-qin
The energy band structures, density of states and optical properties of Ca2Si and P-doped Ca2Si were calculated systemically by density functional theory of the first-principles pseudo potential wave method. The results show that the energy bands of P-doped Ca2Si move to lower energy but it′s still a direct semiconductThe energy band structures, density of states and optical properties of Ca2Si and P-doped Ca2Si were calculated systemically by density functional theory of the first-principles pseudo potential wave method. The results show that the energy bands of P-doped Ca2Si move to lower energy but it′s still a direct semiconductor with the band gap of 0.557 95 eV. The valance bands of orthorhombic P-doped Ca2Si are mainly composed of 3p of Si, 3p of P and 4s, 3d of Ca. The conduction bands mainly composed of 3d of Ca. Furthermore the static dielectric constant, refractive index, the reflectivity, the absorption and the loss function of orthorhombic of P-doped Ca2Si were analyzed in terms of the calculated band structure and densities of states. The results show that the electronic structure and optical properties of Ca2Si can be effectively modulated by P-doped..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 43, Issue 8, 816003 (2014)
The Antibacterial Research of CdTe Quantum Dots Modified the Polysulfone Hollow Fiber Membranes
SUN Meng-na, NI Liu-song, HE Lei, ZHANG Chen, ZHANG Huan, XU Shi-chao, WEI Jun-fu, WANG Bing, ZHANG Ji-mei, and DAI Zhao
The polysulfone hollow fiber membranes is one of the most widely used membranes in many fields due to its unique property, microbial fouling of membrane is one of the most severe challenges duing the application of the hollow fiber membrane. Quantum dots have been widely applied to inhibit the growth of microorganisms The polysulfone hollow fiber membranes is one of the most widely used membranes in many fields due to its unique property, microbial fouling of membrane is one of the most severe challenges duing the application of the hollow fiber membrane. Quantum dots have been widely applied to inhibit the growth of microorganisms due to its small particle size, toxicity and other characteristics. This paper studies the antibacterical properties of CdTe quantum dots modified polysulfone hollow fiber membranes. The qualified CdTe quantum dots showing narrow and symmetric emission spectrum were successfully prepared in aqueous phase, Fluorescence Spectrum (FS) and TEM measurements were employed to characterized the CdTe, and its average size was calculated to b e 3nm. Benzophennone was used as photosensitizer, the polysulfone hollow fiber membrane was prepared by continuous ultraviolet photografting polymerization of β-Hydroxyethyl methacrylate onto membrane surface. Quantum dots were successfully assembled to the surface of the membranes due to the reaction between the hydroxyl group and carboxyl group, infrared spectroscope was employed to confirmed the modified membranes.Wild stranin B1 with average size of about 10μm was isolated the and cultivated, the morphology of wild strain B1 was characterized by scanning electron microscope and polarizingmicroscope. The antimicrobial capability of Quantum dots modified polysulfone hollow fiber membrane was estimated by optical density via ultraviolet spectrophotometer. The data showed that the optical density of the aqueous bacteria was decreased from 0.88 to 0.27 after quantum dots modified memebrane was applied, and consequently, the antibacterial performance of the modified membranes was improved evidently. Results indicated that the technique of continuous ultraviolet photografting polymerization shows a promising potential for modification of hollow fiber membranes in industrial scale..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 43, Issue 8, 816004 (2014)
Effect of Chirp Coefficient on Pulse Splitting and Spectral Properties of Femtosecond Pulse
WANG Zhen-dong, WU Xiao-mei, LIU Ting-ting, MA Jian-ling, and XIAO Jing
The effect of chirp coefficient (C) on pulse splitting and spectral properties of femtosecond Gaussian pulse propagating in a three-level Λ-type atomic medium were investigatedby using the numerical solution of the full Maxwell-Bloch equations without the slowly varying envelope and the rotating-wave approximations.It The effect of chirp coefficient (C) on pulse splitting and spectral properties of femtosecond Gaussian pulse propagating in a three-level Λ-type atomic medium were investigatedby using the numerical solution of the full Maxwell-Bloch equations without the slowly varying envelope and the rotating-wave approximations.It is shown that,when area of the chirped pulse is smaller than or equal to 3π,regardless of size of the C,pulse splitting doesn′t occur,but the oscillation of the spectral component near the central frequency becomes more severe with the increasing of the C; when the 4π area pulse with smaller value of C propagates in the mediums,pulse splitting occurs,but the splitting doesn′t occur for the 4π area pulse with bigger value of C; and the oscillation of the spectral component near the central frequency becomes more severe and the pulse spectral bandwidth and the strength of the spectral component with higher frequency decrease obviously with the increasing of the C.For the pulse with larger area 8π,the case of pulse splitting is similar to 4π pulse,the pulse spectral bandwidth and the strength of the spectral component with higher frequency are not varied evidently with the increasing of the C,but distributions of peak values of the spectral component with higher frequency are very different for the puls with different values of the C..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 43, Issue 8, 819001 (2014)
The Transformation from Electromagnetically Induced Transparency to Lasing Without Population Inversion Based on Spontaneously Generated Coherence
LI Xiao-li, MENG Xu-dong, WU Yan-hua, SHANG Ya-xuan, and ZHANG Lian-shui
The transformation from electromagnetically induced transparency to amplification without inversion based on spontaneously generated coherence was studied by proposing a lambda type three-level system. Three transparency windows are observed when two ground state hyperfine levels are driven by a microwave field. The trThe transformation from electromagnetically induced transparency to amplification without inversion based on spontaneously generated coherence was studied by proposing a lambda type three-level system. Three transparency windows are observed when two ground state hyperfine levels are driven by a microwave field. The transparency shifts into amplification by using the coupling of electromagnetically induced transparency and spontaneously generated coherence with appropriate angle. The results show that there is no population inversion between the ground state and the excited state level and no population inversion between two ground state hyperfine levels when amplification is observed, but the system must go through population inversion of two ground state levels in the process of generating amplification. The populations of two ground state levels can be controlled though the adjustment of the frequency detuning of the microwave field to facilitate the generation of amplification..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 43, Issue 8, 819002 (2014)
Nonlinear Propagation for Stacked Pulses by Cross-phase Modulation
WANG Wen-long, TAN Chao, and FU Xi-quan
The nonlinear propagation model was used to research the nonlinear propagation and Peak-to-Average Power Ratio (PAPR) of the stacked pulses based on cross-phase modulation between the sub-pulses. It is found that when the sub-pulses of the stacked pulse all overlapped, time-coherent will lead to interaction between theThe nonlinear propagation model was used to research the nonlinear propagation and Peak-to-Average Power Ratio (PAPR) of the stacked pulses based on cross-phase modulation between the sub-pulses. It is found that when the sub-pulses of the stacked pulse all overlapped, time-coherent will lead to interaction between the sub-pulses and change the quality of sub-pulses in the process of propagation. Under the condition of different sub-pulses delay, the intensity and PAPR of the stacked pulse occur different degrees of change during the propagation, and their variation amplitude decreases with the sub-pulses delay. For the Gaussian stacked pulse, the pulse shape can basically remain unchanged in the process of nonlinear propagation when the sub-pulses delay is about 3; while the super-Gaussian stacked pulse is about 2.2..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 43, Issue 8, 819003 (2014)
Focusing Analysis on Optical System of Three Line Array Stereoscopic Mapping Camera
WANG Hong, and TIAN Tie-yin
For the imaging quality problem which induced by the deviations from the CCD imaging target surface to the best image plane position of three linear array stereo mapping camera, the focusing precision was calculated according to the design parameters of the optical system ,and effect of the telecentric system on the maFor the imaging quality problem which induced by the deviations from the CCD imaging target surface to the best image plane position of three linear array stereo mapping camera, the focusing precision was calculated according to the design parameters of the optical system ,and effect of the telecentric system on the mapping accuracy was analyzed. Telecentric system is adopted to meet the requirement of stereoscopic mapping , the focusing range is about ±2 mm, and the distortion can be negligible within focusing range. After focusing, the optical system imaging quality and distortion meet the requirement of high accuracy of mapping..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 43, Issue 8, 822001 (2014)
Micro-optics Beam Expander Technology for Infrared Jamming Simulator
REN Zhi-bin, MA Chi, JIN Chuan-guang, and ZHAO Huan-yi
A microlenses array beam expander system was design based on the infrared jamming technology with two jamming light paths.The microlenses array was fabricated by melting photoresist technology,the energy collection efficiency of the jamming simulation system was tested.The results show that the tested energy collectionA microlenses array beam expander system was design based on the infrared jamming technology with two jamming light paths.The microlenses array was fabricated by melting photoresist technology,the energy collection efficiency of the jamming simulation system was tested.The results show that the tested energy collection efficiencys of two jamming light paths are 27.3% and 26.9%,which are consistent with the design result 30.8%.This study verifies the application value of microlenses array as the beam expander element in the infrared jamming simulator and can provide references for the engineering research of infrared imaging simulation technology and infrared imaging target simulator with multiple jamming light paths..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 43, Issue 8, 822002 (2014)
Design of LED Collimator for Uniform Illumination with Double Freeform Surfaces
MENG Xiang-xiang, LIU Wei-qi, FENG Rui, WEI Zhong-lun, ZHOU Min, and YANG Jian-ming
A LED collimator with double freeform surfaces was designed for uniform illumination in both near field and far field.The collimator includes refractive part and reflective part,and each part has double freeform surfaces.Based on Malus Law,the constant optical path length equations that realize the rays collimating werA LED collimator with double freeform surfaces was designed for uniform illumination in both near field and far field.The collimator includes refractive part and reflective part,and each part has double freeform surfaces.Based on Malus Law,the constant optical path length equations that realize the rays collimating were derived.Then associating with tangent-plane iterative method,the date both up freeform surface and down freeform surface simultaneously could be calculated.The simulations show that,84.55% of the energy is collected in ±2° for 1 mm×1 mm size white LED after considering the Fresnel loss,reflective surfaces loss and material absorbing.The uniformity in near field is 94.59%, and the uniformity in far field is 89.01%.The uniformity in near field and the optical efficiency in ± 4° are above 90% and 83.5% respectively,while the LED chip sizes are under 2 mm×2 mm.It is illustrated that the LED collimator can realize uniform illumination in both near field and far field with high light efficiency and the tolerance meet the requirements of alignment..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 43, Issue 8, 822003 (2014)
Study on Uniformity of LED Array Illumination Distribution on Target Plane
WANG Jia-wen, SU Zhou-ping, YUAN Zhi-jun, and ZHU Yi-qing
Global optimization algorithm was proposed to optimize and design LED array for generating uniform illumination distribution on target plane. An evaluation function reflecting illumination uniformity was constructed, which can reach the minimum by optimizing the LEDs positions. While the evaluation function takes the mGlobal optimization algorithm was proposed to optimize and design LED array for generating uniform illumination distribution on target plane. An evaluation function reflecting illumination uniformity was constructed, which can reach the minimum by optimizing the LEDs positions. While the evaluation function takes the minimum value, the optimal LED array can produce highly uniform illumination distribution on target plane. The minimum value of evaluation function was found by simulated annealing algorithm, so that the circular array consisting of 12 LEDs, 4×4 and 4×5 rectangular LED array were optimized. After optimization, the three arrays produce highly uniform illumination distribution with the calculated uniformity 97%, 96% and 95%, respectively. The results show that the optimal radius of circular array does not depend on the number of LEDs.The optimal radius depends linearly on the distance between LED array plane and the target plane. For the rectangular array, the optimal separation between adjacent LEDs depends linearly on the distance between LED array plane and the target plane.The results of the proposed method were consistent with existing method, and the algorithm is simple and convenient..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 43, Issue 8, 822004 (2014)
Design of Ultra Wide-angle Digital Universal Projection Lens
LI Wei-shan, CHEN Chen, SONG Tao, ZHANG Yu, and LIU Xiao-chan
To solve defects and deficiencies of the existing ultra wide-angle digital projection lens and match the ultra wide-angle projecting from different types and specs of digital projectors, a type of ultra wide-angle digital universal projection lens composed of nine lenses was designed. The focal length is 8.76 mm, the fTo solve defects and deficiencies of the existing ultra wide-angle digital projection lens and match the ultra wide-angle projecting from different types and specs of digital projectors, a type of ultra wide-angle digital universal projection lens composed of nine lenses was designed. The focal length is 8.76 mm, the full field of view reaches 97°, F-number is 2.12, BFL is longer than 34 mm, the largest diameter is less than 96 mm and the total optical length is shorter than 200 mm. By setting an effective even aspheric, the off-axial aberrations and distortion are corrected well. By reducing the number of lens and increasing the relative aperture, illumination is improved. By increasing the aperture coma of the system and reducing the FOV of image, relative illumination is improved up to 97.46%. By determining the prim thickness and adjusting the structure and layout, the lens can match prisms of different effective optical thicknesses from 16.5 mm~23 mm in several kinds of digital projector engines. The resolution is 120 lp/mm, and the absolute value of relative distortion is less than 1.5%. The design indicates that the lens can match digital projectors by using 3LCD and 1DLP technologies with the chip sizes from 0.55 in to 0.76 in, minimum projection ratio is up to 0.53∶1 and the largest frame offset reaches 389 mm. Its image quality is excellent with advantages of simple structure, small size, low cost and mass produced..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 43, Issue 8, 822005 (2014)
Design of Multi-Parameter Tunable Bragg Waveguide Grating Filter
ZHANG Ai-ling, and LI Yu-xiang
In order to solve the problem of poor tuning performence of the optical arbitrary waveform generator based on fiber Bragg grating and piezoelectric transducer, a novel multi-parameter fast tunable Bragg grating filter on lithium niobate crystal was proposed. Theory analysis shows that its Bragg wavelength and corresponIn order to solve the problem of poor tuning performence of the optical arbitrary waveform generator based on fiber Bragg grating and piezoelectric transducer, a novel multi-parameter fast tunable Bragg grating filter on lithium niobate crystal was proposed. Theory analysis shows that its Bragg wavelength and corresponding phase is tunable in a linear way with wavelength tuning efficiency of 15.6 pm/V and phase tuning efficiency of 0.2 π/V, and the output light intensity of the filter is controlled by adjusting a polarization rotator also. Simulation results based on transfer matrix theory show that the maximum filtering reflectivity is achieved with the etching duty cycle 1/2, reflectivity more than 98.4% and bandwidth wider than 0.14 nm is obtained when etching depth is deeper than 100 nm on the condition of 10.87 mm grating length, and increasing the wavelength tuning voltage will further reduce the filter bandwidth..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 43, Issue 8, 823001 (2014)
Research on Shared Anode Used for the Large Area Array MCP Detector
SONG Juan, ZHAO Bao-sheng, SHENG Li-zhi, LIU Zhe, DAI Jin-fei, LIU Yong-an, and ZHOU Yan-nan
The development of signal acquisition system used for the large area array of microchannel plate detector is very difficult. Multi-channel shared anode was put forward to solve this technical issue. Dual-channel shared anode and four-channel shared anode were designed.Acording to the basic standard that multi-channel SThe development of signal acquisition system used for the large area array of microchannel plate detector is very difficult. Multi-channel shared anode was put forward to solve this technical issue. Dual-channel shared anode and four-channel shared anode were designed.Acording to the basic standard that multi-channel Shared anode instead of single channel anode, signal transmission characteristics and collection efficiency were tested.Simulation experiment results show that signal transmission in multi-channel shared anode without attenuation and distortion, and the experimental results and simulation results are identical with each other; dual-channel shared anode′s total count rate and four-channel shared anode′s count rate are approximately equal to the sum of single channel anode count rate, the relative error of the count rate are 5.2%、7.4% respectively. Four-channel shared anode can replace single channel anode and dual-channel shared anode,and the number of channels about electronics acquisition system is reduced to 1/4 of the original.So ,the volume, weight and power of the whole acquisition system are reduced effectively..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 43, Issue 8, 823002 (2014)
Effects of Electrostatic-Discharge on GaN-Based High Voltage Light-Emitting Diode
HAN Yu, GUO Wei-ling, FAN Xing, YU Xin, and BAI Jun-xue
GaN-based high-voltage green light-emitting diodes were biased by negative Human-Body-Mode electrostatic discharge (ESD) with -500,-1 000,-2 000,-3 000,-4 000,-5 000 and -6 000 V.The I-V characteristic and luminous flux under different electrostatic shock voltages were comparative analyzed after each shock.The results GaN-based high-voltage green light-emitting diodes were biased by negative Human-Body-Mode electrostatic discharge (ESD) with -500,-1 000,-2 000,-3 000,-4 000,-5 000 and -6 000 V.The I-V characteristic and luminous flux under different electrostatic shock voltages were comparative analyzed after each shock.The results show that the LED has a soft breakdown which accompanied with apparent increased reverse leakage current and unapparent luminous flux change ,which due to the generation of defect after ESD stressing at -500,-1 000,-2 000,-3 000 and -4 000V;When the device was biased to -5 000 V and -6 000 V,a sharp decrease of luminous flux appears,even decay to 50% of light output than before stressing.And forward voltage and reverse leakage current show a large degree of decrease and increase respectively after ESD shock of -6000V,which is due to the thermal model breakdown at this moment.The thermal model breakdown make temperature rise rapidly and form a melting channel,which disabled the LED eventually..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 43, Issue 8, 823003 (2014)
Focusing and Defocusing Characteristics of Square-aperture Planar Microlens Array with Gradient Refractive Index
SHI Hong-yan, and ZHOU Su-mei
To improve filling factor of planar microlens arrays, square-aperture planar microlens arrays with good performance was fabricated with photolithography and thermal ion-exchanging technology, their fill factors was 100%. Imaging characteristics of unit lens and region among the four adjacent lens units (be called corneTo improve filling factor of planar microlens arrays, square-aperture planar microlens arrays with good performance was fabricated with photolithography and thermal ion-exchanging technology, their fill factors was 100%. Imaging characteristics of unit lens and region among the four adjacent lens units (be called corner area) of square-aperture planar microlens arrays were analyzed theoretically and experimentally. Imaging characteristics in corner area are reverse to those in focusing element lens, which is showed by ray tracing and MATLAB simulation. Results with image testing system show that a reversed real image of object is formed after the ray passes through unit lens, while an erect virtual image is obtained because of divergent light out from corner area, which is caused by different refractive index distribution in these two areas. Therefore, square-aperture planar microlens arrays achieve the function of focusing and defocusing. Moreover, with enough ion-exchanging time, the uniform refractive index region in the corner area is so little that a new-type gradient refractive distribution is formed which increases gradually out from the center..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 43, Issue 8, 823004 (2014)
The Transducer Sensitivity of Racetrack Optical Micro-ring Resonator with Feedback
BU Tian-rong, CHEN Yao, HE Peng-cheng, WAN Ling-yu, and DING Yu-li
A racetrack micro-ring sensor with feedback loop was proposed,which make up of a U feedback waveguide,a racetrack cavity and a sensitive ring. The normalized transmission formula of the sensor was derived by Coupled-Mode theory.The effects of the transmission loss factor,the coupling factor and sensitive ring size of sA racetrack micro-ring sensor with feedback loop was proposed,which make up of a U feedback waveguide,a racetrack cavity and a sensitive ring. The normalized transmission formula of the sensor was derived by Coupled-Mode theory.The effects of the transmission loss factor,the coupling factor and sensitive ring size of sensor on the normalized optical intensity were numerically analyzed. The results show that the normalized optical intensity is very sensitive to the transmission loss factor of the sensitive ring. As long as the transmission loss factor changes tinily,the normalized optical intensity changes greatly. When the sensitive ring works on the condition of weak coupling,the sensor may obtain high sensitivity. And the size of sensitive ring has great influence on sensing sensitivity,adjusting the size of sensitive ring properly,the sharp normalized optical spectra were got. Based on the results,the optimized structural parameters were given. The optimization of micro-ring structure can not only output sharp steep asymmetric Fano resonance spectral lines,but also obtain a high Fano resonance spectral slope,which was better to enhance the sensor sensitivity. For a measurement system of 30 dB signal-to-noise ratio,a detection limit can reach to 4.48×10-8 refractive index units in the optimized feedback racetrack micro-ring sensor..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 43, Issue 8, 823005 (2014)
Lensless Ghost Imaging Experiments in Three Different Configurations
XUE Yu-lang, WAN Ren-gang, FENG Fei, YAO Yin-ping, and ZHANG Tong-yi
To achieve stand-off sensing applications,ghost imaging experiments with pseudothermal light were performed from transmissive to reflective cases.First, ghost images of a transmissive double-slit aperture were retrieved in a setup that both the reference beam and signal beam were collected with two different regions ofTo achieve stand-off sensing applications,ghost imaging experiments with pseudothermal light were performed from transmissive to reflective cases.First, ghost images of a transmissive double-slit aperture were retrieved in a setup that both the reference beam and signal beam were collected with two different regions of a single CCD.Then a CCD and a separate bucket detector were used to record the light intensity information of the reference beam and the signal beam,respectively.By calculating the intensity correlation function of the signal beam with no spatial light distribution and the spatial dependent reference beam that does not interact with the object,ghost images of a transmissive object and a reflective object were achieved.In order to design and develop prototype systems field applicable,detailed experimental investigations were performed to compare the effect of system parameters on the quality of imaging in the transmission configuration.The results show that enough high power of light source,large sample numbers,and proper exposure time and spatial frequency bandwidth can lead to ghost image with good resolution and visibility..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 43, Issue 8, 823006 (2014)
Controlled Two-way Quantum Teleportation via GHz Quadripartite Entangled State and Security
HU Yu-an, and YE Zhi-qing
A scheme for controlled two-way quantum teleportation of unknown one-qubit state via GHZ quadripartite entangled state was proposed.Two sides of communication (Alice and Bob) and the controller,secretly share two pairs of GHZ quadripartite entangled state in advance to construct quantum channel.According to the differeA scheme for controlled two-way quantum teleportation of unknown one-qubit state via GHZ quadripartite entangled state was proposed.Two sides of communication (Alice and Bob) and the controller,secretly share two pairs of GHZ quadripartite entangled state in advance to construct quantum channel.According to the different ways of distribution along with different measuring vectors choosed to use,two-way quantum teleportation controlled by a third party and a fouth party were realized.After communication,Alice and Bob perform quantum projection measurement on parts of their qubits respectively.If the controller agrees to intercommunication,he should measure his qubits and announce the results via classical channel.Then the both sides of communication can make appropriate unitary transformations on their own certain qubit on the basis of the controller′s results,thus they are able to reconstruct each other′s unknown state on their own qubit.The security of the whole two-way communication is greatly impoved owing to the join of the third party Charlie and the fourth party Dennis..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 43, Issue 8, 827001 (2014)
Controllable Time Evolution of Coherence of an Atom Bit inside Cavity by Manipulating the Atom Bit Outside Cavity
ZHOU Bing-ju, PENG Zhao-hui, and LIU Xiao-juan
Considering two atom bits in Bell state initially, one bit was injected into a vacuum cavity to produce resonance while leaving the other outside. The controllable coherence of an atom bit inside the cavity was investigated by manipulating the atom bit outside the cavity. For the cases of before and after the Hadamard,Considering two atom bits in Bell state initially, one bit was injected into a vacuum cavity to produce resonance while leaving the other outside. The controllable coherence of an atom bit inside the cavity was investigated by manipulating the atom bit outside the cavity. For the cases of before and after the Hadamard, Hadamard-like, Y, and phase logic gate manipulations on the atom bit outside the cavity, the correlation of two kinds of initial Bell state was discussed by numerical calculation. The time evolution curves of off-diagonal elements in the reduced density matrix for the atom bit inside the cavity was studied. The results show that the off-diagonal elements of the density matrix for the atom bit inside the cavity are zero at any moment before operating the atom bit outside the cavity. That is, the atom bit inside the cavity is always in a mixed state or classical states, and its coherence is always suppressed. However, after Hadamard gate and Hadamard-like gate operations and ground state measurements, off-diagonal elements in the reduced density matrix of the atom bit inside the cavity show the 2π period time evolution, and the coherence can be restored except (2n+1)π/2. At nπ the maximal coherence superposition state and general coherence superposition state were prepared, and a R∧(π/2) rotation correlation existed between the two kinds of Bell states. In addition, performing Y gate and phase gate operations on the outside atom bit, the coherence for the inside atom bit cannot restore. The necessary condition for the restoration of the coherence of the inside atom bit was found out as following: while logic gate operations manipulate the interactions between the atom bit inside the cavity and its environment, and the two atom bits are separated from the field, a strongly coherent entanglement is necessary between the two atom bits..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 43, Issue 8, 827002 (2014)
Multistable Optical Response of a Ladder-type Atom-assisted Optomechanical System
HAN Ming, GU Kai-hui, LIU Yi-mou, ZHANG Yan, and CUI Cui-li
The optical response of a hybrid system,where a Ladder-type three -level atomic ensemble was confined in a optomechanical microcavity with an oscillating mirror in one end,was investigated by solving the Heisenberg-Langevin equations analytically and numerically.The results show that the steady-state behaviors of the oThe optical response of a hybrid system,where a Ladder-type three -level atomic ensemble was confined in a optomechanical microcavity with an oscillating mirror in one end,was investigated by solving the Heisenberg-Langevin equations analytically and numerically.The results show that the steady-state behaviors of the oscillating mirror and the atomic ensemble relate to the elastic coefficient of the spring and the Rabi frequency of the classical pump field.As the elastic coefficient decreases and pump Rabi frequency increases,the atomic ensemble and entire optomechanical system will present multiple steady-state solutions with different steady-state numbers in different frequency domains.Therefore,the steady-state optical response of the system could be controlled by manipulating the Rabi frequency of the classical pump field and the spring elastic coefficient.These results may have potential applications in the area of quantum information processing and high-precision quantum measurement..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 43, Issue 8, 827003 (2014)
Fabrication of Multifunction Anti-oil Antireflection Coatings
FU Xiu-hua, WU Guan-qi, LIU Dong-mei, KOU Yang, and HAN Fang
In order to improve the contamination resistance of optical lens surface,the new anti-oil fluorine material which contains organic indium-tin oxide, thin film material, TiAl alloys and SiO2 were chosen as coating materials. Film system was designed by the aid of TF-Calc software. The films were prepared by vacuum coatiIn order to improve the contamination resistance of optical lens surface,the new anti-oil fluorine material which contains organic indium-tin oxide, thin film material, TiAl alloys and SiO2 were chosen as coating materials. Film system was designed by the aid of TF-Calc software. The films were prepared by vacuum coating equipment and ion beam assist deposition. The results of experiments showed that in different vacuum degree and different film thickness the performance of anti-oil also different. The functional of anti-oil were tested through experiments and the process parameters of deposition were constantly optimized. The average reflectivity of the broadband antireflection coating is below 1% over the wavelength range from 350 to 700 nm. The film is hydrophobic, oleophobic, antifouling, and has high firmness and radiation protection ability, which can be used in various fields such as military, medical and civilian..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 43, Issue 8, 831001 (2014)
The Reflection Properties of Multilayer Anti-counterfeiting Optical films for Vertical-polarized Wave
WANG An-ling, LIU Fu-ping, ZHU Xiao-feng, and YANG Chang-chun
Based on the difference of phase-shift direction and amplitude attenuation direction when the optical wave propagates in conductive medium , with the solution of the wave equation and the boundary conditions of optical wave at the interface of the media, the recurrence formula of thevertical-polarized inhomogeneous optBased on the difference of phase-shift direction and amplitude attenuation direction when the optical wave propagates in conductive medium , with the solution of the wave equation and the boundary conditions of optical wave at the interface of the media, the recurrence formula of thevertical-polarized inhomogeneous optical wave in the multilayer film were derived. In order to exammine the reliability of this method, the light energy reflectivity for an 11-layer combinational film was computed, and the compare of calculating results with the existing calculating method was given. The result shows that the reflection properties of light energy reflectivity get good consistency, but the calculated result with this method displays that metal film has stronger absorbing properties and reflection effective of narrow band..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 43, Issue 8, 831002 (2014)
The Diagnosis of Rayleigh Defect Particle Position by Light Scattering Character on the Optical Surface
GONG Lei, WU Zhen-sen, and PAN Yong-qiang
Based on the polarized bidirectional reflectance distribution function ,the scattering fields of Rayleigh defect particle on the optical surface or inlay the substrate were derived to solve the diagnosis of the particle position. By analysis and discussion of bidirectional reflectance distribution function of pp about Based on the polarized bidirectional reflectance distribution function ,the scattering fields of Rayleigh defect particle on the optical surface or inlay the substrate were derived to solve the diagnosis of the particle position. By analysis and discussion of bidirectional reflectance distribution function of pp about redundant defect particles with different wavelength , the positions of defect particles were identified preliminary. The results show that the sensing degree of wavelength with particles on the substrate is more than particles on the SiO2 coating. Therefore, the position of defect particle is judged by measuring the sensing degree of wavelength. The angle dent appears between 85° and 90° with the defect particles in the Si substrate, while the angle dent appears around 70° with the defect particles in the SiO2 coating. The angle dent is used to judge the particle position further in the project..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 43, Issue 8, 831003 (2014)
Transient Absorption Spectra of Aggregated LHC II in Broypsis Corticulans
HE Jun-fang, ZHU Chang-jun, ZHAO Xiao-xia, and LI Yuan-yuan
A time resolved transient absorption spectroscopy was performed to investigate the photoprotection mechanism in light harvesting complex II of broypsis corticulans. A 667 nm femotosenond laser and white light pulse were used as pump and probe lights. The range and accuracy of the delay line between probe and pump were A time resolved transient absorption spectroscopy was performed to investigate the photoprotection mechanism in light harvesting complex II of broypsis corticulans. A 667 nm femotosenond laser and white light pulse were used as pump and probe lights. The range and accuracy of the delay line between probe and pump were 340 ps and 134 fs, respectively. The experiment results show that the absorption of the probe is dynamically changing after pump light exciting. The results of the multi-exponential fitting, fluorescence emission and excitation spectra show that the transient absorption spectra from 500 nm to 600 nm mainly originate from carotenoids and the aggregated light harvesting complex II contains at least four types of carotenoids functioning photoprotection which have S0→Sn transition spectral properties 511 nm and 554 nm, 522 nm and 541 nm, 530 nm and 563 nm (corresponding to siphonaxanthin), 536 nm and 575 nm. Carotenoids play the photoprotection role not only in a direct manner by quenching the triplet state of chlorophyll a in several picoseconds, but also in an indirect manner by quenching the singlet state of oxygen in several hundreds of picoseconds..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 43, Issue 8, 832001 (2014)
© Copyright 2018-2021 | Chinese Laser Press. All Rights Reserved 沪ICP备15018463号-20