Journals >Acta Photonica Sinica
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2013
Volume: 42 Issue 2
25 Article(s)
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Research Article
Cooperative Energy Transfer in Eu2+-Yb3+ Codoped Phosphate Glasses
XU Bo, YANG Bin, ZHANG Yue-pin, WANG Jin-hao, and XIA Hai-ping
Downconversion luminescence of one UV photon (320 nm) cut into two near-infrared photons (around 1 000 nm) was reported in Eu2+-Yb3+ co-doped phosphate glasses. Absorption, excitation and emission spectra were carried out to demonstrate the occurrence of quantum cutting in this system. The experimental evidences of theDownconversion luminescence of one UV photon (320 nm) cut into two near-infrared photons (around 1 000 nm) was reported in Eu2+-Yb3+ co-doped phosphate glasses. Absorption, excitation and emission spectra were carried out to demonstrate the occurrence of quantum cutting in this system. The experimental evidences of the cooperative energy transfer from Eu2+ to Yb3+ were presented by the decay curves of 5d→4f emission of Eu2+ ions. Luminescence decay curves of Eu2+ emission were recorded as a function of the Yb3+ concentration and analyzed by using Inokuti-Hirayama′s model for energy transfer. Energy transfer efficiency was also calculated to be 23.05% for the Eu2+-1.0Yb3+ co-doped sample, and 53.6% increased for the Eu2+-2.0Yb3+ co-doped sample..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 42, Issue 2, 127 (2013)
High Frequency Electrical Parameter Extraction for Photodetectors Based on Coplanar Waveguide Microstrips
XU Guang-hui, CHAI Guang-yue, HUANG Chang-tong, HE Li-ming, XU Jian, LIAO Shi-dong, and FENG Dan-hua
For no on-wafer measurement of photodetectors (PDs), a simple and effective method to determine high frequency electrical parameters of the equivalent circuit model is presented. Firstly, a coplanar waveguide (CPW) microstrip matched with the microwave probe is designed, and the measured output reflection coefficient sFor no on-wafer measurement of photodetectors (PDs), a simple and effective method to determine high frequency electrical parameters of the equivalent circuit model is presented. Firstly, a coplanar waveguide (CPW) microstrip matched with the microwave probe is designed, and the measured output reflection coefficient shows good agreement with the theoretical design. The chip is mounted on the CPW microstrip and the output reflection coefficient of the PD test-fixture is measured. The equivalent circuit model including the PD, the bondwire and the CPW elements is simulated. By fitting the measured output reflection coefficient of the test-fixture, high frequency electrical parameters of the PD are extracted..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 42, Issue 2, 132 (2013)
Influence of Oblique Beams on Matching Accuracy of Correcting Filter
GAO Shi-zhi, JIN Shang-zhong, and YUAN Kun
Color measurement instruments designed by principle of photoelectric integral, response of photo detector must meet Luther condition, which is realized by matching of correcting filters, and the matching accuracy is relevant to the actual light path in correcting filter. With the impact of measurement condition, the inColor measurement instruments designed by principle of photoelectric integral, response of photo detector must meet Luther condition, which is realized by matching of correcting filters, and the matching accuracy is relevant to the actual light path in correcting filter. With the impact of measurement condition, the incident light inevitably contains various directions, and the exist of oblique beams reduces matching accuracy by theoretical calculation. The accuracy of matching filter is evaluated using the smallest proportion of total error area, the theoretical basis for correcting filter matching is introduced, the influence of oblique beams to correcting filter′s matching accuracy is proved, and the corrected formula of thickness of correcting filter is proposed when taking oblique beams into account. Take the matching of “Y” correcting filter as an example, the significant of corrected formula to matching accuracy is proved..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 42, Issue 2, 135 (2013)
Highly Efficient Organic Light-emitting Devices Achieved by p-type Doped Hole Injection Layer
CHEN Yu, WANG Peng, GUO Run-da, YUE Shou-zhen, ZHAO Yi, and LIU Shi-yong
Organic light-emitting devices based on molybdenum oxide (MoOx) doped 4,4′-bis(carbazol-9-yl)biphenyl (CBP) as a p-type doping hole injection layer was demonstrated. The devices comprise the following structure: ITO/MoOx/CBP∶MoOx/CBP/CBP: tris(2-phenylpyridine)iridium(III)(Ir(ppy)3)/4,7-diphenyl-1,10-phenanthroline(BphOrganic light-emitting devices based on molybdenum oxide (MoOx) doped 4,4′-bis(carbazol-9-yl)biphenyl (CBP) as a p-type doping hole injection layer was demonstrated. The devices comprise the following structure: ITO/MoOx/CBP∶MoOx/CBP/CBP: tris(2-phenylpyridine)iridium(III)(Ir(ppy)3)/4,7-diphenyl-1,10-phenanthroline(Bphen)/LiF/Al, where CBP acts as hole injection layer (HIL) and hole transport layer (HTL) as well as the host metarial of emitting layer (EML). The simple structure also has the the benefit of lowing the injection and transpotring barrier of holes. With the thickness of HIL increasing, the current density of device increases, indicating the p-type doping layer has a good performance of enhancing the holes injection. The performance of the device can be improved through optimizing the thickness of HIL and HTL. The maximum current efficiency of optimized device is 29.8 cd/A, which can be attributed to the more balanced distribution of carrier in EML. It is noteworthy that the efficiency roll-off of optimized device is only 17.7% between maximum and 20 000 cd/m2, comparing to that of conventional device (62.1%). The undoping CBP layer in optimized device can help to extend the distribution zone of excitons, reducing the possibility of triplet-triplet annihilation and triplet-polaron annihilation, this can be accounted for the improved efficiencies and reduced efficiency roll-off..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 42, Issue 2, 139 (2013)
Highly Efficient Tandem P-i-N White Organic Light Emitting Diode Based on a New Charge General Layer
WANG Jin, XIAO Xin-ming, ZHANG Bing, JIANG Wen-long, DING Gui-ying, and XIE Wen-fa
Organic light emitting diodes(OLEDs) were fabricated using 5 wt.% cesium carbonate(Cs2CO3) doped 2,9-Dimethyl-4,7-diphenyl-1,10-phenanthroline(BCP) as eletron-injection layer and 20 wt.% molybdenum oxide(MoO3) doped N, N′-Bis(naphthalen-1-yl)-N,N′-bis(phenyl)-benzidine(NPB) as hole-injection layer, respectively, and thOrganic light emitting diodes(OLEDs) were fabricated using 5 wt.% cesium carbonate(Cs2CO3) doped 2,9-Dimethyl-4,7-diphenyl-1,10-phenanthroline(BCP) as eletron-injection layer and 20 wt.% molybdenum oxide(MoO3) doped N, N′-Bis(naphthalen-1-yl)-N,N′-bis(phenyl)-benzidine(NPB) as hole-injection layer, respectively, and the carrier transfer characteristics were examined. The lowered driving voltage suggests BCP: Cs2CO3 and NPB: MoO3 efficiently enhance carrier injection in OLEDs. Color-stable and efficient tandem P-i-N white organic light emitting diode(WOLED) with a new charge generation layer, which consists of BCP: 5 wt.% Cs2CO3/NPB: 20 wt.% MoO3, has been fabricated. The maximum current efficiency of the two-unit tandem P-i-N orange device is enhanced by 2.5 factors with respect to the one-unit device. Such a connecting structure permits efficient opposite hole and electron injection into two adjacent emitting units and gives tandem devices superior electrical and optical performances. The tandem P-i-N WOLED with the charge generation layer, in which the individual orange phosphorescent and blue fluorescent were used as emissive units, exhibits excellent color stability and higher efeciency. The Commission Internationale de l′Eclairage (CIE) chromaticity coordinates almost focus exactly on (0.33, 0.29) between 500 cd/m2 and 5 000 cd/m2, which closes to the point of equal energy (0.33,0.33). The results may prove the method to be effective to enhance the current efficiency and color-stable of WOLED..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 42, Issue 2, 144 (2013)
Characteristics of Fluorescence Spectrum of Multi-alkali Photocathode of FOP Window
LI Xiao-feng, LU Qiang, and GUO Qian
The characteristics of photoluminescence and the measuring principle of photoluminescence of LLL image intensifier were discussed, and the fluorescence spectrum of multi-alkali photocathode of FOP (optical fiber panel) input window was measured. The test results suggest that the fluorescence spectrum of multi-alkali phThe characteristics of photoluminescence and the measuring principle of photoluminescence of LLL image intensifier were discussed, and the fluorescence spectrum of multi-alkali photocathode of FOP (optical fiber panel) input window was measured. The test results suggest that the fluorescence spectrum of multi-alkali photocathode of FOP window is not a smooth Gauss curve, but a curve with some small interference peaks being added to a Gauss curve, for there are two special light beams in the fluorescence transmitted by FOP window. One light beam is collimated light and the other is the folded light beam at the very moment when the incidence angle is equivalent to critical angle of total reflection. Both light beams have fixed phase difference or optical path. When the difference between the phase differences of the two light beams lives up to the integral multiple of λ, they will interfere to produce constructive interference peak; when the difference between the phase differences of the two light beams lives up to the odd multiple of 1/2λ, they will interfere to produce destructive interference peak. If constructive interference peak is produced exactly at the peak wavelength of fluorescence spectrum, then the measured peak fluorescence intensity is higher than its inherent peak fluorescence intensity; on the contrary, if destructive interference is produced exactly at the peak wavelength of fluorescence spectrum, then the measured fluorescence intensity is lower than its inherent fluorescence intensity. Furthermore, due to the impact of interference, the half peak width of fluorescent curve can not be accurately determined. Hence, the impact of interference factors should be taken into consideration when analyzing the fluorescence spectrum of photocathode of FOP window..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 42, Issue 2, 150 (2013)
First-principles Study on Electronic and Optical Properties of ZnO/GaN-Core/Shell Heterostructures
WU Mu-sheng, YUAN Wen, LIU Gang, WANG Yan, and YE Zhi-qing
The electronic and optical properties of ZnO/GaN-core/shell heterostructures are studied by using the first-principles method based on density functional theory. The results show that the top of valence bands and the bottom of conduction bands for the ［101－0］ and ［112－0］ crystal plane of heterostructures are mainly conThe electronic and optical properties of ZnO/GaN-core/shell heterostructures are studied by using the first-principles method based on density functional theory. The results show that the top of valence bands and the bottom of conduction bands for the ［101－0］ and ［112－0］ crystal plane of heterostructures are mainly contributed by the nitrogen and zinc atoms, respectively. The heterostructures with ［101－0］ lateral facets have the similar imaginary parts of dielectric functions (ε2) curves, which are all electronic transitions between the states from nitrogen at valence bands and the states from zinc at conduction bands. However, the peaks of the ε2 curves shift slightly depending on the thickness of the core and shell. In contrast, the ε2 curve for the heterostructures with ［112－0］ lateral facets is significantly different from the cases with ［101－0］ lateral factets.There is a new peak related to the transition between the states from gallium and the states from nitrogen. Therefore, the optical properties of the ZnO/GaN-core/shell heterostructures can be tuned by controlling the lateral facets of the heterostructures.The current work is available for the applications in light emitting device,photoelectric solar cell,and biological detection..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 42, Issue 2, 156 (2013)
Structural Phase Transition, Electronic Structures and Optical Properties of GaN
LI Jian-hua, CUI Yuan-shun, and CHEN Gui-bin
Equation of state and phase transformation under high pressure of two phases GaN have been calculated by means of plane wave pseudo-potential method with generalized gradient approximation. The electronic density of states, band structure and optical properties of change mechanism have been discussed near the point of Equation of state and phase transformation under high pressure of two phases GaN have been calculated by means of plane wave pseudo-potential method with generalized gradient approximation. The electronic density of states, band structure and optical properties of change mechanism have been discussed near the point of phase transformation. the transition pressure of wurtzite and rock salt structure GaN is 43.9 Gpa and 46.0 Gpa by means of the equation of state and enthalpy equal principle respectively; The typical direct bandgap semiconductor of GaN became indirect bandgap semiconductor material on the structural phase transition process. Compared rock salt structure GaN with wurtzite, the main peak of the dielectric constant increases, the intrinsic absorption edge shift to high energy apparently. The optical properties of rock salt structure GaN is worse than wurtzite structure in the low energy region..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 42, Issue 2, 161 (2013)
Photonic Crystal Three-wavelength Power Splitter Based on Directional Coupling
LI Lei, LIU Gui-qiang, CHEN Yuan-hao, and TANG Fa-lin
A photonic crystal coupling structure is designed by introducing two parallel single mode defect waveguides with one row coupling rods in between them in the two-dimensional (2D) triangular lattice array. Based on the analysis of coupling and decoupling property of the coupled photonic crystal waveguides, it is known tA photonic crystal coupling structure is designed by introducing two parallel single mode defect waveguides with one row coupling rods in between them in the two-dimensional (2D) triangular lattice array. Based on the analysis of coupling and decoupling property of the coupled photonic crystal waveguides, it is known that different normalized frequencies correspond to different coupling lengths. The coupling lengths for coupled waveguides at different frequencies are calculated to design a new super-tiny photonic crystal three-wavelength power splitter by the plane wave expansion method and the principle of directional coupling. The effect of splitting the beam with normalized frequencies of 0.369, 0.394 and 0.435 are obtained. The function of the power splitter is analyzed by using finite different time domain method. The simulation results show that it has a good splitting beam effect. The result should contribute to the research over new kinds of optical filters, directional couplers, wavelength division multiplexers, polarization beam splitter, optical switches and other photonic devices..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 42, Issue 2, 167 (2013)
Effect of Changing Surface Structure of Photonic Crystals on Image
TIAN Shuang, and TONG Yuan-wei
Negative index material is one of wide research objects because of its unique characteristics, especially perfect imaging of photonic crystal slab. Silicon is a kind of the most widely applied materials in the integrated optical field because of its physical properties. In this paper, Si cylindrical rods are designed iNegative index material is one of wide research objects because of its unique characteristics, especially perfect imaging of photonic crystal slab. Silicon is a kind of the most widely applied materials in the integrated optical field because of its physical properties. In this paper, Si cylindrical rods are designed into hexagonal pattern in air to build a 2D photonic crystals flat. Band structure of this photonic crystals is calculated by the plane wave expansion method and the finite difference time domain method is used to simulate the effect on imaging when the surface structure of photonic crystals flat is changed. The simulation results show that photonic crystals slab can still image but image intensity will change by changing the both outermost radius or shifting outermost layer column laterally as photonic crystal slab equivalent refractive index is －1. And the position of image change and it changes accord with the classic Veselago relation of photonic crystal imaging as the surface structure of photonic crystals slab is changed in a certain range. But the phase difference of image and source will be 180° if the surface changes beyond this range and at the same time the image position will change sharply and the source and image will go against the Veselago relation. From the results it can be included that it can change the image intensity, position and phase effectively by changing the surface structure of photonic crystal slab..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 42, Issue 2, 171 (2013)
Tunable Negative Refraction Photonic Crystals Filled with Liquid Crystals
YANG Ming-wei, XIAO Jun, and LI Rui
Tunable negative refraction photonic crystals have attracted much attention for their potential application value. The photonic crystal with a square lattice of Si cylinders surrounded by optically controlled liquid crystals is investigated. The plane wave expansion method is used to calculate the equi-frequency surfacTunable negative refraction photonic crystals have attracted much attention for their potential application value. The photonic crystal with a square lattice of Si cylinders surrounded by optically controlled liquid crystals is investigated. The plane wave expansion method is used to calculate the equi-frequency surface (EFS). The General Snell′s Law and EFS analysis method is used to ensure the ability of tunable refraction. A new photonic crystal filled with liquid crystal structure is designed. Numerical simulation result shows that this kind of tunable negative refraction photonic crystal filled with optically controlled liquid crystals can be achieved. Compared with electronically controlled one, this way has a faster response speed and a more simple structure, which may be used in optically controlled router and all optical networks..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 42, Issue 2, 176 (2013)
Optimal Design of Narrowband Filter in Oblique Incidence Based on Genetic Arithmetic
YU Kan, LIAO Jian-feng, ZHANG Xiao-dan, BAO Jia-qi, and YIN Juan-juan
According to the polarization characteristics of the thin film narrowband filter, the stack of narrowband filter used in oblique incidence is provided based on the genetic arithmetic in this paper. A 100GHz five-cavity thin film filter used in 18° incidence is optimized based on the programme. The stack can eliminAccording to the polarization characteristics of the thin film narrowband filter, the stack of narrowband filter used in oblique incidence is provided based on the genetic arithmetic in this paper. A 100GHz five-cavity thin film filter used in 18° incidence is optimized based on the programme. The stack can eliminate the phenomenon of polarization light central wavelength separation used in oblique incidence and it has low polarization dependent loss. It can be used as an angle-tuned thin film filter for wavelength modulation. Compared with the thin film filter stack obtained by needle arithmetic design, it has higher rectangle degree, larger wavelength tunable range and less polarization dependent loss. The experimental results show it meets the demand of design and its tunable range is more than 25 nm..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 42, Issue 2, 181 (2013)
Simulation of Strain Distribution of GaAs Nanoparticles with Growth in Different Environment
JIANG Zi-xiong, ZHANG Qiu-long, and YUAN Cai-lei
The growth of nanoparticles embedded in a host matrix can lead to substantial strain. Strain can have much influence on the crystal growth and microstructure development of nanoparticles and thecorrelation of the physical properties of nanoparticles with their microstructures. To better understand and control the physiThe growth of nanoparticles embedded in a host matrix can lead to substantial strain. Strain can have much influence on the crystal growth and microstructure development of nanoparticles and thecorrelation of the physical properties of nanoparticles with their microstructures. To better understand and control the physical properties of GaAs nanoparticles, it is fundamentally necessary to study the strain distribution of nanoparticles embedded in different thin films.In this paper, the growth strain of GaAs nanoparticles embedded in Al2O3 and SiO2 thin films were investigated. Finite element calculations clearly indicate that the GaAs nanoparticles incurs a net deviatoric strain in both amorphous Al2O3 and SiO2 thin films. The compressive strain existing in the center of a GaAs nanoparticle embedded in Al2O3 thin film is stronger than that at the surface of the nanoparticle. In contrast, the compressive strain existing at the surface of a GaAs nanoparticle embedded in SiO2 thin film is stronger than that in the center of the nanoparticle. It is possible to control the strain distribution of GaAs nanoparticles by embeding the GaAs nannoparticles in different thin films, which will futher influence the microstructures and morphologies of GaAs nanoparticles. Strain engineering is an effective tool for tailoring the properties of GaAs nanoparticles..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 42, Issue 2, 186 (2013)
Synthesis and Photochromic Performance of a Hyperbranched Azo Polyurethane
FENG Zong-cai, SONG Xiu-mei, JIANG Shu-yi, and HUANG Xiang-lan
Using 4-((3,4-dihydroxyphenyl)diazenyl)benzenesulfonic acid and 4,4′-diphenyl- methane diisocyanate (MDI) as raw materials, the hyperbranched azo polyurethane was synthesized by A2+B3 polycondensation, with the reactions between phenolic hydroxy or sulfo group and isocyanate group. Then the peripheral hydroxyls of syntUsing 4-((3,4-dihydroxyphenyl)diazenyl)benzenesulfonic acid and 4,4′-diphenyl- methane diisocyanate (MDI) as raw materials, the hyperbranched azo polyurethane was synthesized by A2+B3 polycondensation, with the reactions between phenolic hydroxy or sulfo group and isocyanate group. Then the peripheral hydroxyls of synthetic hyperbranched azo polyurethane reacted with succinic anhydride or trimellitic anhydride to to improve the polymer solubility. The target hyperbranched azo polyurethanes were characterized by IR, TG and UV-Vis spectrum. The UV-Vis spectra showed that both of the maximum absorption peaks of π→π* in the unmodified hyperbranched azo polyurethane and the hyperbranched azo polyurethane modified by trimellitic anhydride were the same, at 425 nm, while the maximum absorption peak of π→π* in hyperbranched azo polyurethane modified by succinic anhydride was red shifted to 501 nm..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 42, Issue 2, 191 (2013)
Tunable Plasmonic Properties of Gold Hollow-core Semi-shell Nanofilms
ZHANG Xing-fang, and YAN Xin
The gold hollow-core semi-shell nanofilms with different thicknesses were fabricated by depositing gold onto a cleaned glass support covered with a close-packed monolayer of 200 nm diameter polystyrene spheres and subsequently by the removal of the PS spheres. The thicknesses of gold nanofilms can be controlled by the The gold hollow-core semi-shell nanofilms with different thicknesses were fabricated by depositing gold onto a cleaned glass support covered with a close-packed monolayer of 200 nm diameter polystyrene spheres and subsequently by the removal of the PS spheres. The thicknesses of gold nanofilms can be controlled by the deposition time, the morphologies and optical properties of gold films were obtained by field emission scanning electron microscopy and home-built spectrometer respectively, and the relationship between morphologies and tunable plasmonic properties was also discussed. Then, using 4-aminothiophenol (4-ATP) as the probe molecule, the surface enhanced Raman scattering signals of 4-ATP adsorbed on the films after immersing the nanofilms into the 4-ATP solution were measured by Raman spectrometer with the excitation wavelength of 785 nm. The results show that the localized surface plasmon resonance wavelength of gold nanofilm red shifts as the film thickness increases, and the resonance wavelength can be tuned over a wide range from visible band to infra-red band; moreover, when the resonance wavelength of nanofilms is close to the incident excitation wavelength, the surface enhanced Raman scattering signals can be obtained obviously, indicating that the fabricated nanofilms can be used as the potential surface enhanced Raman substrates. The reasons of the shift of the spectral peak and SERS intensity of different nanofilms were also discussed..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 42, Issue 2, 196 (2013)
Photon Double-slit Diffraction with Quantum Theory Approach
YAN Li-yun, LI Hong, LIU Xiao-jing, WANG Jing, ZHANG Si-qi, WU Kun-peng, LI Chun-hong, WU Xiang-yao, and GUO Yi-qing
In this paper, the light double-slit diffraction with quantum theory approach is studied. Firstly, the light wave function in slits is calculated, and the diffraction wave function is obtained with Kirchhoff′s law.The diffraction intensity is proportional to the diffraction wave function da party. Futhermore, the intenIn this paper, the light double-slit diffraction with quantum theory approach is studied. Firstly, the light wave function in slits is calculated, and the diffraction wave function is obtained with Kirchhoff′s law.The diffraction intensity is proportional to the diffraction wave function da party. Futhermore, the intensity formula of light double-slit diffraction is obtained; by comparing the quantum theory calculation results and classical electromagnetic theory calculation results and the experimental date, it is found that the calculate result of quantum theory is in accordance with the experment data, but the classical electromagnetic theory calculation result with the experiment date has certain deviation. So, the quantum theory can explain the light diffraction more precisely.The proposed method can also further study the light of the single slit,many slits and grating diffraction experiment phenomena..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 42, Issue 2, 200 (2013)
An Optimal Frame Size Algorithm for Quantum Signaling Based on the Fidelity
GAO Yin-chao, and NIE Min
In order to solve the problem of quantum signaling optimal frame size, a quantum signaling optimal frame size algorithm based on the fidelity was proposed. Firstly, a basic quantum signaling transceiver model was analyzed. Then, a joint fidelity of quantum signaling which consists of several quantum states was defined.In order to solve the problem of quantum signaling optimal frame size, a quantum signaling optimal frame size algorithm based on the fidelity was proposed. Firstly, a basic quantum signaling transceiver model was analyzed. Then, a joint fidelity of quantum signaling which consists of several quantum states was defined. Finally, the optimal frame size algorithm was given by calculating the link effective utilization. Simulation result is consistent with the theory, which proves that the proposed algorithm is feasible and simple and can be applied to complicated practical environments..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 42, Issue 2, 205 (2013)
Coherent Population Trapping of a Three-level Atom Interacting with Few Cycle Pulse Train
CAI Xun-minga, and FAN Meng-huib
The poulation transfer and coherent population trapping of a three-level atom interacting with few cycle pulse train are studied. The density matrix equation in interation picture is numerical solved without rotating wave approximation. The research indicates that if a three-level atom interacts with a few cycle pulse The poulation transfer and coherent population trapping of a three-level atom interacting with few cycle pulse train are studied. The density matrix equation in interation picture is numerical solved without rotating wave approximation. The research indicates that if a three-level atom interacts with a few cycle pulse train, the population transfer of level and the coherence of ground state will be gradual accumulated. When the repetition frequency of pulses is integer points of the ground-state splitting, the three atom interacts with pulse train can be seen as the atom interacts with two tenoning frequency of the frequency comb. So the system will be in the dark state and reach coherent population trapping. If the parameters of few-cycle pulse are appropriately selected, the coherence of three-level system will evolute into stable value in 0.5 nanosecond. The coherent population trapping in the three-level is generated. Comparing with the pulse that the pulse width is 100 femtoseconds, the build-up time of coherent population trapping by few cycle pulse train is shortened two orders of magnitude. When the ground-state splitting is wided enough and the carrier frequency of pulse is ω=(ω1+ω2)/2, where, are the atomic transition frequency, the doppler frequency shift that is aroused by the movement of atom won’t destroy the coherent population trapping of atom. The reason is that all tenoning frequencies of the frequency comb have the same frequency shift, so the condition of coherent population trapping is still meeted..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 42, Issue 2, 209 (2013)
A Novel Method for Subsurface Damage Measurement of Optical Components
TIAN Ai-ling, WANG Hui-ting, DANG Juan-juan, and WANG Chun-hui
Subsurface damages produced in grinding process will influence optical performance and lifetime of optical elements. The testing for subsurface damage of polished surface is research hot and difficult point now. Combination of confocal image, tomography technology, microscope optics, optical scatter and weak signal proSubsurface damages produced in grinding process will influence optical performance and lifetime of optical elements. The testing for subsurface damage of polished surface is research hot and difficult point now. Combination of confocal image, tomography technology, microscope optics, optical scatter and weak signal processing, a novel method based on laser confocal microscope tomography is proposed. The effects of different sizes of pinhole on measure accuracy are analyzed, and the cross section microstructure picture of the subsurface damage sample is given. The subsurface damage depth is about 45 μm with this novel method. For the same K9 glass, the subsurface damage depth is about 50~55 μm with the chemical corrosion treatment technology. The measurement results are basically consistent. Comparison with the destructive etching method shows that this novel method is good for polished surface in quantitative and non-destructive..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 42, Issue 2, 214 (2013)
Research on Quality Analysis and Measurement of Stereoscopic Display
SHEN Li-li, ZHANG Jing, FAN Ke-feng, and FU Bei-bei
3D display technology has become the frontier and hot issue in recent yesrs, and its display quality is gradually caused attention.For quality measurement of stereoscopic display, test methods of the crosstalk, angle crosstalk, brightness, the difference of binocular brightness and the brightness uniformity difference 3D display technology has become the frontier and hot issue in recent yesrs, and its display quality is gradually caused attention.For quality measurement of stereoscopic display, test methods of the crosstalk, angle crosstalk, brightness, the difference of binocular brightness and the brightness uniformity difference of stereoscopic displays are given in this paper. The most popular LCD display and PDP display samples are selected to detect, and testing values of stereoscopic display with different size are compared. Through experiments, influences of mentioned index on different stereoscopic displays are obtained.Results show PDP displays with active shutter technology have a large watching angle and a lower crosstalk than LCD displays..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 42, Issue 2, 219 (2013)
Measurement and Analysis of Aircraft LRCS in Outfield Test
YANG Ting-wu, ZENG Xiao-dong, and WANG Hao
The measurement of aircraft LRCS is of crucial importance for the detection system evaluation and the characteristic research of the laser scattering from aircraft. A brief introduction of the measuring theory of the laser scattering from the target is presented in this paper. By analyzing the measuring condition in ouThe measurement of aircraft LRCS is of crucial importance for the detection system evaluation and the characteristic research of the laser scattering from aircraft. A brief introduction of the measuring theory of the laser scattering from the target is presented in this paper. By analyzing the measuring condition in outfield test, the laser systems and test steps are designed for full size aircraft LRCS and verified by the experiment in laboratory. The processing data error 7% below is obtained of the laser radar cross section by using Gaussian compensation and elimination of sky background for original test data. The of measurement and analysis proves that the proposed method is effective and correct to get laser radar cross section data in outfield test..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 42, Issue 2, 224 (2013)
Infrared Small Target Fast Detection Based on Local Saliency
XUE Song, and HAN Guang-liang
For the problem of small target detection in infrared image, a method based on the local saliency is proposed. The feature on the local gray-scale of small targets in infrared image is analyzed, and a criterion is proposed to check the feature of peak value. Based on the criterion to check peak value and the characteriFor the problem of small target detection in infrared image, a method based on the local saliency is proposed. The feature on the local gray-scale of small targets in infrared image is analyzed, and a criterion is proposed to check the feature of peak value. Based on the criterion to check peak value and the characteristic of small target on time domain, a fast algorithm is designed. Firstly, local max points are selected and the follow-up computing is limited to these points to reduce the computation. Then peak values are checked based on the decline of gray-scale. Finally, false targets caused by noise are removed based on the continuity between frames. Experiments show that this algorithm has a high processing speed, and can effectively filter out the random noise in the image..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 42, Issue 2, 228 (2013)
Two-Dimensional Arimoto Entropy Linear-type Threshold Segmentation Method
ZHANG Hong, and FAN Jiu-lun
Arimoto entropy is a general form of entropy. Firstly, a representation error on the two-dimensional Arimoto entropy is pointed out, and a correct two-dimensional Arimoto entropy thresholding method is given; a two-dimensional Arimoto entropy linear-type thresholding method and its fast recursive formula are proposed; Arimoto entropy is a general form of entropy. Firstly, a representation error on the two-dimensional Arimoto entropy is pointed out, and a correct two-dimensional Arimoto entropy thresholding method is given; a two-dimensional Arimoto entropy linear-type thresholding method and its fast recursive formula are proposed; Arimoto entropy formula parameter selection and the segmentation performance assessment according to the ground truth images are discussed. A large number of segmentation experiment results show that the two-dimensional Arimoto entropy linear-type thresholding method has at least a similar effect with the two-dimensional Arimoto entropy & the two-dimensional Renyi entropy linear-type thresholding; in the cases of the more image edge and noise information, the two-dimensional Arimoto entropy linear-type method is better than the two-dimensional Arimoto entropy & the two-dimensional Renyi entropy linear-type method, is a effective thresholding method..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 42, Issue 2, 234 (2013)
Multiple Resolution Bilateral Filter for Infrared Clutter Suppression
ZONG Jing-guo, QIN Han-lin, LIU De-lian, YUAN Sheng-chun, and ZHAO Xiao-ming
Complex background is a major factor in the performance of the infrared search and tracking system. In this paper, an infrared clutter suppression method based on multi-resolution bilateral filter is proposed to solve the problem. Firstly, nonsubsampled contourlet transfrom is adopted to decompose the input infrared scComplex background is a major factor in the performance of the infrared search and tracking system. In this paper, an infrared clutter suppression method based on multi-resolution bilateral filter is proposed to solve the problem. Firstly, nonsubsampled contourlet transfrom is adopted to decompose the input infrared scene images, which extracts multi-scale and directional detail features of the image. Then, according to the difference between target and background clutter signal, bilateral filter is introduced to suppress background details and enhance target information for suppression background. Several groups of experimental results demonstrate that the proposed method can detect the infrared target image effectively, compared with classical infrared scene background suppression methods, such as two-dimensional least means square..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 42, Issue 2, 241 (2013)
Gyrator Transform Hologram and Its Application in Image Encryption
LIN Rui
The gyrator transform hologram is proposed. The generation and the reconstruction of the gyrator transform hologram are simulated by using the fast algorithm for computing the gyrator transform. This new type hologram based on phase-shifting digital hologram is also studied. A novel method is proposed for optical imageThe gyrator transform hologram is proposed. The generation and the reconstruction of the gyrator transform hologram are simulated by using the fast algorithm for computing the gyrator transform. This new type hologram based on phase-shifting digital hologram is also studied. A novel method is proposed for optical image encryption by using sinusoidal phase gratings based on the methods mentioned above. In this proposal method, the angle of gyrator transform, the frequency and the rotation angle of the gratings are regarded as the encryption keys according to the rotation properties of the gyrator transform in the phase space. Two or more cascaded gyrator transform systems are applied to realize the image encryption. The simulation experiments are performed with two cascaded gyrator transform systems on the basis of the phase-shifting digital hologram. The results confirm the feasibility, validity and the secure performance of the proposal method..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 42, Issue 2, 245 (2013)
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