Contents
2007
Volume: 27 Issue 11
33 Article(s)
Export citation format
Atmospheric Optics and Oceanic Optics
Statistical Study of Energy-Optimized Distribution for Sand-Dust Detection Using Airborne Lidar
[in Chinese], [in Chinese], [in Chinese], and [in Chinese]
The minimum laser pulse energy to detect sand-dust with the polarized 532 nm perpendicular channel and 1064 nm channel with airborne atmospheric lidar are analyzed statistically according to American ANSI standard and sand-dust extinction coefficient profiles detected by ground-based lidar from 1999 to 2004 year in HefThe minimum laser pulse energy to detect sand-dust with the polarized 532 nm perpendicular channel and 1064 nm channel with airborne atmospheric lidar are analyzed statistically according to American ANSI standard and sand-dust extinction coefficient profiles detected by ground-based lidar from 1999 to 2004 year in Hefei area. The laser pulse eye-safety maximal energy with different beam divergence angles and energy ratio (532 nm and 1064 nm) are simulated in 0～12 km altitude is simulated for the airborne atmospheric lidar. Two laser pulse energy distribution schemes are presented according to the eye-safety standard on the ground, detection ability for two “bottle-neck” channels and statistical results of sand-dust extinction profile in Hefei..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 27, Issue 11, 1913 (2007)
Atomic and Molecular Physics
Study on Structure and Photoelectron Spectroscopy about Sin-1N and Sin-2N2(n=3～8) Ion Clusters
[in Chinese], [in Chinese], [in Chinese], [in Chinese], [in Chinese], and [in Chinese]
The method of B3LYP/ 6-311G (d) in density functional theory (DFT) was used to optimize the geometric configuration and study the photoelectron energy spectroscopy of Sin-1N and Sin-2N2 (n=3～8) ion clusters, and the results were found as follows: first, the ground-state structures of the clusters were obtained, and theThe method of B3LYP/ 6-311G (d) in density functional theory (DFT) was used to optimize the geometric configuration and study the photoelectron energy spectroscopy of Sin-1N and Sin-2N2 (n=3～8) ion clusters, and the results were found as follows: first, the ground-state structures of the clusters were obtained, and the symmetry of Sin-2N2 (n=3～8) ion clusters was better than Sin-1N (n=3～8). Second, there was a transition from planar to spacial structures at n=4 and n=6. For Sin-1N (n=3～8), the structure was planar when n≤4, and the other was spacial structure. For Sin-2N (n=3～8), the structure was planar with n=6, and the other was spacial structure. Finally, the structure with even n was more stable than those with odd n in Sin-1N+ (n=3～8) clusters; the structure with odd n was more stable than those with even n in Sin-1N-, Sin-2N-2 and Sin-2N+2 (n=3～8) clusters..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 27, Issue 11, 1920 (2007)
Monte Carlo Simulation of Parametric Excitation of Atoms in a Quadrupole Trap
[in Chinese], [in Chinese], [in Chinese], and [in Chinese]
In the experiment of magnetic trapping of neutral atoms, the current noise in the coils will excite the atomic motion, which influences greatly the temperature and the lifetime of the trapped atoms. For anharmonic trap, this excitation has energy-selective characters, and depends on the frequency spectrum of the currenIn the experiment of magnetic trapping of neutral atoms, the current noise in the coils will excite the atomic motion, which influences greatly the temperature and the lifetime of the trapped atoms. For anharmonic trap, this excitation has energy-selective characters, and depends on the frequency spectrum of the current noise. The quadrupole trap is chosen as a research object, which is widely used in experiment. The direct simulation Monte Carlo method is used to model the phenomenon of parametric excitation of the atomic motion in the quadrupole trap, and the excitation frequency dependences of the temperature and the trap loss of the atoms are studied. The temperature of the atom cloud is calculated further as the functions of the modulation time and the modulation depth at the two resonant peaks. Furthermore, the influences of the elastic collision rate on the temperature increase of the atom cloud in the process of parametric excitation are also addressed. These results are valuable reference for the experiment of parametric excitation in a quadrupole trap..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 27, Issue 11, 1929 (2007)
Fiber Optics and Optical Communications
Study and Fabrication of All-Fiber Microring Resonator
[in Chinese], [in Chinese], [in Chinese], [in Chinese], and [in Chinese]
Ring resonators have been playing a very important role in the design and fabrication of active and passive optical devices due to their small size, multi-function and compactness. Bend loss characteristics of optical fiber are investigated thoroughly, and the results show that all-fiber resonator with smaller ring radRing resonators have been playing a very important role in the design and fabrication of active and passive optical devices due to their small size, multi-function and compactness. Bend loss characteristics of optical fiber are investigated thoroughly, and the results show that all-fiber resonator with smaller ring radius, wider free spectral range (FSR), higher fineness (f) and quality factor (Q) can be achieved only by microfiber. Based on the improved fused taper technique, under the condition of slow change and adiabatic condition, a 5 μm-radius high-quality microfiber with uniform waist length of 80 mm is fabricated. And utilizing self-wrapping coupling method, an all-fiber microring resonator with 500 μm radius is realized, which exhibits good resonant response. This all-fiber device is expected to avoid the large bendloss and connection loss induced by planar waveguide integration..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 27, Issue 11, 1935 (2007)
Study of Pulse Width Effect on Performance of Optical Code-Division Multiple-Access En/Decoder
[in Chinese], [in Chinese], and [in Chinese]
Optical en/decoder is one of the key factors affecting the performance of optical code-division multiple-access (OCDMA) system. The mathematical model of OCDMA en/decoder based on phase-shifted superstructured fiber Bragg grating (SSFBG) with low reflectivity is presented, and the performance of SSFBG en/decoder is invOptical en/decoder is one of the key factors affecting the performance of optical code-division multiple-access (OCDMA) system. The mathematical model of OCDMA en/decoder based on phase-shifted superstructured fiber Bragg grating (SSFBG) with low reflectivity is presented, and the performance of SSFBG en/decoder is investigated with different input pulse width as well as grating chip length. Here, the auto-correlation ratios of PA to the maximum wing level (P/W) and cross-correlation level (P/C) are used to quantitatively evaluate the en/decoder performance, and the curves of the relationship between P/W, P/C and pulse width as well as the grating chip length are obtained. From the analysis of simulation result, we can see when the pulse width and grating chip length meet some condition, optimum en/decode performance can be obtained, namely, an appropriate grating chip length en/decoder can be selected accroding to input pulse width, which can result in a better system performance..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 27, Issue 11, 1939 (2007)
Novel Read/Write Independently Controlled All-Optical Buffer Based on Dual-Semiconductor Optical Amplifier
[in Chinese], [in Chinese], and [in Chinese]
All-optical buffer can store the packet, which can solve the problem of node collision when transmitting packets in optical domain, and will become an important element in all-optical network. This paper presents a novel erasable all-optical buffer which realizes the “write” and “read” function. Two semiconductor opticAll-optical buffer can store the packet, which can solve the problem of node collision when transmitting packets in optical domain, and will become an important element in all-optical network. This paper presents a novel erasable all-optical buffer which realizes the “write” and “read” function. Two semiconductor optical amplifiers (SOA) which are used as the nonlinearity element can also compensate the power attenuation at the same time. Compared with the single semiconductor optical amplifier configuration, the storage time is prolonged greatly when the same signal power is introduced. This configuration can overcome the “packet leakage” effectively on the output port because of the “write” operation. The buffer can store the packet transmitting at the speed of 2.5 Gb/s successfully..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 27, Issue 11, 1945 (2007)
Active Time-Domain Addressing Technique for Fiber Bragg Grating Sensor Array
[in Chinese], [in Chinese], [in Chinese], and [in Chinese]
A novel interrogation technology with the function of real-time monitoring for fiber Bragg grating (FBG) sensor system based on a ring-cavity fiber laser, and a 1×4 analog electronic switch is reported. A cascaded wavelength-division-multiplexed FBG sensor array is acted as the reflector of the laser. Letting signA novel interrogation technology with the function of real-time monitoring for fiber Bragg grating (FBG) sensor system based on a ring-cavity fiber laser, and a 1×4 analog electronic switch is reported. A cascaded wavelength-division-multiplexed FBG sensor array is acted as the reflector of the laser. Letting signal light obtain sufficient gain by adjusting the optical route and increasing the intensity of pump light, then laser pluses working at Bragg wavelength of each element will output orderly by introducing the technique of wavelength scanning with a tunable Fabry-Pérot filter. A 1×4 analog electronic switch is employed. The laser pluses are allocated to 4-output channels in time-sequence. Demodulated with an unbalanced Michelson scanning interferometer, a 4-element array is addressed successfully. Working with a wavelength of 1555 nm, the system is demonstrated to be with a sensing sensitivity of 1.630°/με, which agrees with the theoretical value of 1.674°/με..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 27, Issue 11, 1950 (2007)
Holography
Optimized Parameters for Nonvolatile Holographic Recording in (Fe,Cu)∶LiNbO3Crystals
[in Chinese], [in Chinese], [in Chinese], [in Chinese], and [in Chinese]
The photo-excitation coefficient, electron recombination coefficient and bulk photovoltaic coefficient of Cu in LiNbO3 are obtained. The effects of doped composition ratio of the deeper and shallower trap centers, oxidization-reduction state on the recording sensitivity and dynamic range are simulated numerically. The The photo-excitation coefficient, electron recombination coefficient and bulk photovoltaic coefficient of Cu in LiNbO3 are obtained. The effects of doped composition ratio of the deeper and shallower trap centers, oxidization-reduction state on the recording sensitivity and dynamic range are simulated numerically. The crystal conditions for simultaneously optimizing sensitivity and dynamic range are also investigated. The results show that, it is available to choose doping concentration of shallower trap centers as 5.0×1025 m-3 and doping concentration of deeper trap centers as 3×1024～3×1025 m-3 to achieving the larger sensitivity and dynamic range simultaneously in the practical applications..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 27, Issue 11, 1955 (2007)
Theoretical Investigation and Optimization of Nonvolatile Holographic Recording in (Ce,Cu)∶LiNbO3CrystalLi Dashan
[in Chinese], [in Chinese], [in Chinese], [in Chinese], and [in Chinese]
Based on the band transport model, the two-center nonvolatile holographic recording in (Ce,Cu)∶LiNbO3 has been theoretically investigated and optimized. Microphysical parameters of (Ce,Cu)∶LiNbO3 crystal are obtained and used to rigorously solve two-center band transport equations by numerical algorithm. The effects ofBased on the band transport model, the two-center nonvolatile holographic recording in (Ce,Cu)∶LiNbO3 has been theoretically investigated and optimized. Microphysical parameters of (Ce,Cu)∶LiNbO3 crystal are obtained and used to rigorously solve two-center band transport equations by numerical algorithm. The effects of recording and sensitizing intensities, dopant concentration of Ce and Cu, and microphysical parameters on recording performance of two-center holographic recording have been analyzed. And the characteristic of two-center recording in (Ce,Cu)∶LiNbO3 crystal has been found, that the deep center Cu plays a key role in the recording process and a strong space-charge field has been built in Cu traps, so a high diffraction efficiency and fixing efficiency can be achieved. Numerical results have been verified by experiments. The highest saturation and fixing diffraction efficiencies achieved are 60.5% and 53.8%, respectively..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 27, Issue 11, 1960 (2007)
Imaging Systems
An Imaging Approach of Two-Dimensional Object with Subwavelength Periodic Structure Based on Moiré Technique
[in Chinese], and [in Chinese]
When the measuring grating is pulled and/or rotated relative to the reference grating, both of the spatial period and the direction of moiré fringes are studied by photonics method in moiré technique, so does the stop of measuring grating. An approach of imaging of two-dimensional object with subwavelength peWhen the measuring grating is pulled and/or rotated relative to the reference grating, both of the spatial period and the direction of moiré fringes are studied by photonics method in moiré technique, so does the stop of measuring grating. An approach of imaging of two-dimensional object with subwavelength periodic structure is given based on the fact that spatial period of diffractive wave may be larger than measuring grating's one in moiré technique. First, two-dimensional object with subwavelength periodic structure can be encoded by a perpendicular grating so that homogeneous waves can be obtained. Second, passing through the optical system designed specially, the well-distributed waves with evanescent waves can be enlarged so that it can be recognized by CCD camera. Third, the homogeneous waves with evanescent waves can be decoded by a decoding grating. By decoding, the information of encoding grating is filtered, the image of two-dimensional object with subwavelength periodic structure can be reappeared in the image plane. By the approach given, superresolution image of two-dimensional object with subwavelength periodic structure will be obtained. Theoretical analysis and experimental design for the imaging process of two-dimensional object with subwavelength structure are given well by photonics method. At the same time, the directions of filters as well as the main factors of the imaging are discussed in the novel technique..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 27, Issue 11, 1967 (2007)
Study of the Magnetic Mirror Device to Enhance the Photoelectron's Accumulation Time
[in Chinese], [in Chinese], [in Chinese], [in Chinese], [in Chinese], [in Chinese], and [in Chinese]
The essential factors of enhancing the detecting limitation of low-light imaging system are enough accumulation time to the light signal. After the principle is demonstrated for the accumulation time of CCD to low temperature, it shows the localization and complexity. So, we put forward a device for promoting the low-lThe essential factors of enhancing the detecting limitation of low-light imaging system are enough accumulation time to the light signal. After the principle is demonstrated for the accumulation time of CCD to low temperature, it shows the localization and complexity. So, we put forward a device for promoting the low-light level imaging system' detection limit in which a magnetic mirror structure is coupled between the photocathode and the photoelectron acceptor (screen target), viz. this is the method of microchannel electron vase plate. It can be used in the small-scale integration imaging system respectively to enhance the detection limit of low-light level by the new way. The new photoelectron acceptor can assure the image signal's accumulation time. By this new way, the signal-to-noise of imaging system can be improved and detection limit of low-light imaging system is expanded. The physics principle of the field of magnetic mirror is demonstrated and the simulation values showed the expected result sensitive detection limit 10-11 lx can be realized at the room temperature instead low temperature..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 27, Issue 11, 1973 (2007)
Instrumentation, Measurement and Metrology
Full-Field Strain Measurement Based on Least-Square Fitting of Local Displacement for Digital Image Correlation Method
[in Chinese], and [in Chinese]
In order to obtain reliable strain field , full-field strain measurement based on least-square fitting of local displacement for digital image correlation method is proposed. The principle of digital image correlation (DIC) method is introduced,and full-field strain measurement based on local least-square fitting is exIn order to obtain reliable strain field , full-field strain measurement based on least-square fitting of local displacement for digital image correlation method is proposed. The principle of digital image correlation (DIC) method is introduced,and full-field strain measurement based on local least-square fitting is expatiated, strain calculation near the border, hole and crack are also discussed. The results from homogeneous deformation test and the tensile test of the aluminum specimen with a hole in the center obviously demonstrated the validity of this technique. Large strain calculating window is recommended to use in case of homogeneous deformation,so calculation results approach true value; For inhomogeneous deformation, large calculating window should be selected to according to the noise level of the local displacement field, but when displacement field has high accuracy, smaller calculating window is selected..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 27, Issue 11, 1980 (2007)
Measurement Model of Focusing and Leveling Measurement System for Projection Lithography Tool
[in Chinese], and [in Chinese]
Image quality is the key performance of the optical lithography tool and it relies on the performance of wafer focusing and leveling measurement system. A measurement model of single probe spot for focusing and leveling measurement system is established. The relationship formula of the height of exposure field and the Image quality is the key performance of the optical lithography tool and it relies on the performance of wafer focusing and leveling measurement system. A measurement model of single probe spot for focusing and leveling measurement system is established. The relationship formula of the height of exposure field and the position on sensitive detector is simplified according to the approximation calculation rules derived from wafer mapping standard and integrated circuit size standard. Height and tilts of the exposure field can be calculated on basis of multiple probe spots by using least square method and surface fitting with a plane. Comparing with traditional model, this model can analyze focusing and leveling measurement system with higher accuracy of 10 nm, and can be used in developing lithographic tool with less than 100 nm critical dimension..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 27, Issue 11, 1987 (2007)
Measure of Optical Errors Based on Harvey-Shack Surface Scattering Theory
[in Chinese], [in Chinese], and [in Chinese]
Scattering effects from optical fabrication errors of different frequency-segment limit the optical performance. But there lacks appropriate optical design software to account for these effects. In order to solve this problem and guide fabrication, Wavelet transform is used to separate errors; and then Harvey-Shack surScattering effects from optical fabrication errors of different frequency-segment limit the optical performance. But there lacks appropriate optical design software to account for these effects. In order to solve this problem and guide fabrication, Wavelet transform is used to separate errors; and then Harvey-Shack surface scatter theory is used to specify optical surface. Because of wavelet-transform's character, the corresponding region of crucial frequency segment error is also found when the optical performance cannot satisfy demand, thereby guiding fabrication. Finally, there is an experimental validation via measurement data of an aperture =500 mm mirror and design demand “the enclosed energy requirement of 70% in a 0.33 mrad enclosed region”. The experimental results show the method can set up a direct relation between frequency-segment errors, optical specification and optical fabrication effectively..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 27, Issue 11, 1992 (2007)
Real-Time Surface Profile Measurement Using Sinusoidal Phase-Modulating Interferometry
[in Chinese], [in Chinese], and [in Chinese]
A sinusoidal phase-modulating (SPM) interferometer for real-time surface profile measurement is proposed and analyzed. A laser diode and a high-speed image sensor are used as the light source and the photo detector. The phase corresponding to each measurement point on the surface is calculated by a signal processing ciA sinusoidal phase-modulating (SPM) interferometer for real-time surface profile measurement is proposed and analyzed. A laser diode and a high-speed image sensor are used as the light source and the photo detector. The phase corresponding to each measurement point on the surface is calculated by a signal processing circuit. The surface profile is obtained by the phase distribution . The interferometer is insensitive to vibrations of the optical components and fluctuations in the light source. The surface profile of an optical wedge was measured . For 60×60 measurement points, the measurement time was less than 8.2 ms. Repeatability in the measurements was 4.3 nm..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 27, Issue 11, 1997 (2007)
Lasers and Laser Optics
Experimental Study of Fiber Ring Laser with Single Polarization Controller
[in Chinese], [in Chinese], [in Chinese], [in Chinese], [in Chinese], and [in Chinese]
Physical mechanism of using nonlinear polarization rotation as saturable absorber to obtain pulse is analyzed theoretically.Experimental study of improved femtosecond fiber ring laser is reported. A fiber ring laser with highly Er3+-doped fiber as gain medium is demonstrated, 976 nm laser diode (LD) laser is used as puPhysical mechanism of using nonlinear polarization rotation as saturable absorber to obtain pulse is analyzed theoretically.Experimental study of improved femtosecond fiber ring laser is reported. A fiber ring laser with highly Er3+-doped fiber as gain medium is demonstrated, 976 nm laser diode (LD) laser is used as pump source, and in the fiber ring cavity, nolinear polarization rotation mode-locking is realized by adopting single polarization controller. By tuning polarization controller , stable mode-locked pulses centered at 1535.9 nm with 23.5 nm bandwidth at 3 dB, 131 fs duration and an average output power as high as 5.91 mW are successfully obtained at the repetition rate of 11.20 MHz..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 27, Issue 11, 2003 (2007)
Effect of Laser Polarizations on Surface Instability of Dense Plasma Irradiated by Relativistic Intense Laser Pulses
[in Chinese], [in Chinese], [in Chinese], [in Chinese], [in Chinese], and [in Chinese]
The surface instability of a dense plasma slab irradiated by a relativistic intense laser pulse is investigated using two-dimensional particle-in-cell simulation. When the laser pulse is incident with s-polarization, Rayleigh-Taylor-like instability is observed on the plasma surface. Later the instability propagates inThe surface instability of a dense plasma slab irradiated by a relativistic intense laser pulse is investigated using two-dimensional particle-in-cell simulation. When the laser pulse is incident with s-polarization, Rayleigh-Taylor-like instability is observed on the plasma surface. Later the instability propagates into the plasma bulk forming bubble structures, which propagate forward subsequently. The development of this instability depends upon the initial plasma density. At high densities such as over 20 times of the critical density, this instability is not observed obviously. This surface instability is not formed for the case of p-polarization, i.e., the Rayleigh-Taylor-like instability is anisotropic in three-dimensional geometry. It is expected that this instability can have significant effect on high harmonics generation and ion acceleration..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 27, Issue 11, 2008 (2007)
Reconstruction Algorithm for Laser Intensity Temporal-Spatial Distribution from Measured Temperature Distribution on Target Surface
[in Chinese], [in Chinese], [in Chinese], [in Chinese], and [in Chinese]
The reconstruction expressions of the laser temporal-spatial distribution retrieved from temperature field of the heated surface have been obtained. Becuase the characteristic Abelian kernel function exists in integral representations, the integrations are ill-conditioned and the solutions are instable. In order to solThe reconstruction expressions of the laser temporal-spatial distribution retrieved from temperature field of the heated surface have been obtained. Becuase the characteristic Abelian kernel function exists in integral representations, the integrations are ill-conditioned and the solutions are instable. In order to solve the ill-conditioned problems, the generalized functions theory and regular transformation method are utilized to reconstruct the integral functions. The reconstruction algorithm for laser intensity temporal-spatial distribution from measured temperature distribution on the target-surface is obtained. The sensitivity of the retrieved intensities to measured temperature error is analyzed. The developed algorithms is verified by numerical simulation. The relations of reconstructed intensity errors varying wth target thickness and irradiated time are gained by numerical simulation. The results show that the retrieved intensity distributions accord with those in the initial model for two kinds of boundary conditions on the back surface. The algorithm can be applied to monitor laser parameters on the target surface under intense laser irradiation..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 27, Issue 11, 2013 (2007)
Materials
Study on High-Brightness Green Organic Light-Emitting Devices Using PS-TPD as Hole Transporting Layer
[in Chinese], [in Chinese], [in Chinese], [in Chinese], and [in Chinese]
The effect of the composite hole transporting layer with different polystyrene (PS)-triphenyl diamine (TPD) mass ratios on the performance of organic light-emitting devices (OLEDs) was investigated. By using this blending system as hole transporting layer, a double-layer organic light-emitting device was fabricated witThe effect of the composite hole transporting layer with different polystyrene (PS)-triphenyl diamine (TPD) mass ratios on the performance of organic light-emitting devices (OLEDs) was investigated. By using this blending system as hole transporting layer, a double-layer organic light-emitting device was fabricated with the structure of indium-tin-oxide (ITO)/polystyrene (PS)∶N,N′-bis(3-methylphenyl)-N,N′-diphenylbenzidine (TPD)/ tris-(8-hydroxyquinoline)-aluminum (Alq3)/Mg∶Ag by the spin-coating technique. For comparison, a similar double-layer device was fabricated using pure TPD as hole transporting layer by thermal vacuum deposition method. The hole drift mobility of PS-TPD thin films with different mass ratios was characterized by time-of-flight method, and electroluminescent characteristics of these devices were measured. Results demonstrated that the hole mobility of blending thin films is 1～2 orders of magnitude lower than that of pure TPD film. When the mass ratio is m(PS)∶m(TPD)=10∶90, the device has a maximum luminance of 14280 cd/m2 and a maximum lumen efficiency of 1.2 lm/W. It was concluded that the incorporation of PS with proper concentration will lower the hole mobility of the functional layer, adjust the hole transporting ability of TPD, more effectively balance the number of positive and negative charge carriers in the recombination zone, and thus enhance the luminance and efficiency of the device..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 27, Issue 11, 2021 (2007)
Splitting Effect in Anisotropic Metamaterial
[in Chinese], [in Chinese], [in Chinese], [in Chinese], and [in Chinese]
An anisotropic metamaterial (AMM) with negative permeability and permittivity tensors is proposed for polarized-beam splitting. By analysis of the propagation of electromagnetic wave in the lossless anisotropic metamaterial and the dependence of transmissivity on the incident angle, the polarized-beam splitting charactAn anisotropic metamaterial (AMM) with negative permeability and permittivity tensors is proposed for polarized-beam splitting. By analysis of the propagation of electromagnetic wave in the lossless anisotropic metamaterial and the dependence of transmissivity on the incident angle, the polarized-beam splitting characteristics of the anisotropic metamaterial with different wave-vector surface depended on the signs and magnitude of the permeability and permittivity tensors are investigated. Based on the analysis, the anisotropic metamaterials with single-lobe hyperboloid wave-vector surface and ellipsoid and double-lobe hyperboloid wave-vector surface are considered as the favorable candidates for polarized-beam splitting. The former can realize the p component or s component positive refraction and the other component negative refraction. Meanwhile, total transmission can exist under some conditions. The latter can realize one component of incident wave total reflection and the other component total transmission under some conditions. The numerical simulations about the propagation of a Gaussian beam from an isotropic regular material in these two anisotropic metamaterials are performed, and the results show that these two anisotropic metamaterials can realize polarized-beam splitting and have the potential to be a new polarized-beam splitter..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 27, Issue 11, 2027 (2007)
Tunable Optical Filter Based on Two-Dimensional Heterostructure Photonic Crystal with Neighboring Dot-Defects and Curved Waveguide
[in Chinese], [in Chinese], [in Chinese], and [in Chinese]
Tunable optical filter based on two-dimensional heterostructure photonic crystal is formed by curved waveguides and neighboring cavities when line and dot defects are introduced into heterostructure photonic crystal. Finite-difference time-domain (FDTD) method is used to analyze the filter. Results showed that the waveTunable optical filter based on two-dimensional heterostructure photonic crystal is formed by curved waveguides and neighboring cavities when line and dot defects are introduced into heterostructure photonic crystal. Finite-difference time-domain (FDTD) method is used to analyze the filter. Results showed that the waves with certain frequencies in the waveguide could be introduced into the cavity when resonance coupling occured. The introduced frequency depends on parameters of curved waveguide and cavities in the heterostructure photonic crystal. When the refractive indices of neighboring medium or radius of the rods were changed, a wide transmission region of 31 nm or 12 nm could be realized respectively. Our results provided a new design method and bases improving the efficiency of add/drop and realizing the tunability of filter..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 27, Issue 11, 2034 (2007)
Medical Optics and Biotechnology
Measurement of Polarized Backscattering Differential Spectra for Tissue Phantom
[in Chinese], [in Chinese], [in Chinese], [in Chinese], and [in Chinese]
A system for measuring polarized backscattering differential spectrum is reported. In the system, linearly polarized light is used to illuminate the sample surface, parallel and perpendicular components of its backscattered light are measured with polarizer and spectroscope, thereafter, the differential spectrum is calA system for measuring polarized backscattering differential spectrum is reported. In the system, linearly polarized light is used to illuminate the sample surface, parallel and perpendicular components of its backscattered light are measured with polarizer and spectroscope, thereafter, the differential spectrum is calculated. Our system is validated by the comparison with Monte Carlo simulation, in which two kinds of polystyrene spheres with diameters of 5.0 μm and 9.0 μm are used. Based on this, the influence of the distribution of sphere size on differential spectrum is studied initially and roughly. Its result shows the differential spectrum can reflect the change of size distribution sensitively. In the mixtures of small and large spheres, when the relative concentrations of large spheres is increased in limited range, the oscillation frequency keeps identical to the small spheres, but differential signal intensity is weaken . It implies the polarized backscattering differential spectra can be used for pre-cancer detection potentially..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 27, Issue 11, 2038 (2007)
The Study of Non-Destructive Measurement of Fruit Internal Qualities Using Spectral Imaging
[in Chinese], [in Chinese], and [in Chinese]
The internal qualities of apple were detected using spectral imaging. The spectral imaging in wavelength of 632 nm, 650 nm, 670 nm, 780 nm, 850 nm and 900 nm were captured. The Lorentzian distribution (LD), Gaussian distribution (GD) and Exponential distribution (ED) with three parameters were used to fit scattering prThe internal qualities of apple were detected using spectral imaging. The spectral imaging in wavelength of 632 nm, 650 nm, 670 nm, 780 nm, 850 nm and 900 nm were captured. The Lorentzian distribution (LD), Gaussian distribution (GD) and Exponential distribution (ED) with three parameters were used to fit scattering profiles for all wavelengths. LD was found to be the best function for fitting gray distribution of imaging. The multi-linear regression model relating Lorentzian parameters to fruit sugar content were development using best single wavelength, double wavelengths, three wavelengths and four wavelengths. The best model with four wavelengths was able to predict apple sugar content with r=0.831. Results show that the multi-spectral scattering imaging is nondestructive, fast and easy to implement, and it can provide a nondestructive means for measuring fruit internal quality..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 27, Issue 11, 2042 (2007)
An Iris Block-Encoding Method Based on Statistic of Local Information
[in Chinese], [in Chinese], and [in Chinese]
Thanks to many advantages of the iris, such as stable, nonintrusive, and unchangeable, iris recognition has been a research hot-subject in the biometrics identification field. However, the abundant textures and complex structures of irises lead to a great number of troubles for feature extraction and encoding. In orderThanks to many advantages of the iris, such as stable, nonintrusive, and unchangeable, iris recognition has been a research hot-subject in the biometrics identification field. However, the abundant textures and complex structures of irises lead to a great number of troubles for feature extraction and encoding. In order to simplify the feature extraction and encoding method and improve the efficiency of iris recognition, an iris block-encoding method based on statistic of local information is proposed. Firstly, it achieves preprocessing of the original eye image, such as iris localization, and gets the normalized iris features image. Secondly, according to the comparative relationships between local information and global information, local information and local information, it accomplishes the iris block-encoding. Thirdly, it calculates the Hamming distance between different iris codes and obtains the recognition result according to Hamming distance. Experimental results demonstrated that the proposed method is effective and feasible. It also has high recognition accuracy and speed..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 27, Issue 11, 2047 (2007)
Methods for the Prediction of Sugar Content of Rice Wine Using Visible-Near Infrared Spectroscopy
[in Chinese], [in Chinese], and [in Chinese]
A new approach of using visible-near infrared spectroscopy combined with different chemometric methods was investigated for the prediction of sugar content of rice wine. 240 wine samples were used for the calibration set, while 60 for the validation set. After some pretreatments of smoothing, standard normal variate (SA new approach of using visible-near infrared spectroscopy combined with different chemometric methods was investigated for the prediction of sugar content of rice wine. 240 wine samples were used for the calibration set, while 60 for the validation set. After some pretreatments of smoothing, standard normal variate (SNV) and first derivative to the spectral data, four different models were developed and the precision were compared, including partial least squares (PLS), combination of wavelet transform and PLS (WT-PLS), combination of principal component analysis and artificial neural network (PCA-ANN), and combination of PCA and least squares-support vector machine (PCA-LS-SVM). According to the standards of correlation coefficient (r), the root mean square error of prediction (RMSEP) and bias, a best calibration model of PCA-LS-SVM was achieved for the prediction of sugar content of rice wine. The correlation coefficient r=0.962, RMSEP=0.021 and Bias=-0.001 by PCA-LS-SVM, and a satisfying prediction precision was achieved. The results indicated that visible-near infrared spectroscopy could be successfully applied for the prediction of sugar content of rice wine and PCA-LS-SVM model could achieve a best prediction results..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 27, Issue 11, 2054 (2007)
Nonlinear Optics
2 μm KTiOAsO4Optical Parametric Oscillator
[in Chinese], [in Chinese], [in Chinese], [in Chinese], and [in Chinese]
In order to confirm that KTiOAsO4 can be used in optical parametric oscillator (OPO) to generate 2 μm laser, the pulsed 2 μm KTA OPO which uses θ=49°-cut KTA as a nonlinear crystal to generate 2 μm laser light is designed. The oscillation threshold of the OPO is calculated. The signal and idle wavelengths are measIn order to confirm that KTiOAsO4 can be used in optical parametric oscillator (OPO) to generate 2 μm laser, the pulsed 2 μm KTA OPO which uses θ=49°-cut KTA as a nonlinear crystal to generate 2 μm laser light is designed. The oscillation threshold of the OPO is calculated. The signal and idle wavelengths are measured near 2.16 μm and 2.09 μm which are in agreement with theoretical value. And the pulse width is also measured. By using the mirrors whose transmittance are 60%,70％,90％ respectively as the output mirrors of OPO, the output energy and the electro-optic efficiency are detected. And the impact of the reflectivity of output mirror on output energy is tested and the relationship between the output energy and OPO cavity length is got. So the fesibility of using KTA crystal in OPO to generate 2 μm laser light is demonstrated, which can be the theoretical basis for the next research work..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 27, Issue 11, 2059 (2007)
Optical Devices
Angular Position Sensitive Detector and Finite-Element Analysis
[in Chinese], [in Chinese], and [in Chinese]
The structure design of angular position sensitive detector (APD) utilizing semiconductor′s lateral photo electric effect is introduced. A finite-element method (FEM) is adopted to analyze and calculate the output characteristics of APD, such as linearity, angular precision and response sensitivity. Based on FEM simulaThe structure design of angular position sensitive detector (APD) utilizing semiconductor′s lateral photo electric effect is introduced. A finite-element method (FEM) is adopted to analyze and calculate the output characteristics of APD, such as linearity, angular precision and response sensitivity. Based on FEM simulation, this APD design can achieve high linearity (<0.04%) and high precision (~20″) for angular measurement in the range of 90°. At last, the factors that influence the precision of measuring angle including electric parameters of material and model structure parameters, such as resistance and electrode, are analyzed. By optimizing material and structure, the APD can achieve higher linearity (<0.01%) and angle resolution (<1″) and be used in angular measurement with high resolution..
Acta Optica Sinica
- Publication Date: Jun. 19, 2020
- Vol. 27, Issue 11, 2064 (2007)
OPTOELECTRONICS
Second Harmonic Generation of GeS2-Ga2S3-CdS Chalcogenide Transparent Surface Crystallized Glasses
[in Chinese], [in Chinese], and [in Chinese]
Chalcogenide glass of GeS2-Ga2S3-CdS system was prepared by heat inducting. The results of X-ray diffraction (XRD), transmission spectrum and scanning electron microscope (SEM) showed that transparent surface microcrystal glass containing CdGa2S4 has been gained. The second harmonic generation (SHG) effect of the microChalcogenide glass of GeS2-Ga2S3-CdS system was prepared by heat inducting. The results of X-ray diffraction (XRD), transmission spectrum and scanning electron microscope (SEM) showed that transparent surface microcrystal glass containing CdGa2S4 has been gained. The second harmonic generation (SHG) effect of the microcrystal glass was studied by Maker-fringe technique, and the result indicated that CdGa2S4 in the glass induced the occurrence of SHG effect. The isotropy of the glass was broken when CdGa2S4 was growing preferentially on the surface of the microcrystal glass, and two enveloping Maker-fringes were obtained. And the maximum of relative second harmonic (SH) intensities appeared at incidence angle around ±(35°～50°) which was 8 times as that of α-quartz single crystal. When CdGa2S4 was growing non-preferentially on the surface of the microcrystal glass, only one enveloping Maker-fringe was obtained because of the strong scattering from CdGa2S4 grains. That is the maximum relative SHG intensities which appeared at incidence angle of 0..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 27, Issue 11, 2070 (2007)
Quantum Optics
Application of Phase Retrieval Algorithm to Quantum Correlated Diffraction Imaging
[in Chinese], [in Chinese], [in Chinese], [in Chinese], and [in Chinese]
With our research going deeply, quantum correlated diffraction imaging can be accomplished by use of classical thermal source now, which indicates its wide application in X-ray and neutron diffraction imaging. The object transmission functions are successfully retrieved from the lensless Fourier transform frequency speWith our research going deeply, quantum correlated diffraction imaging can be accomplished by use of classical thermal source now, which indicates its wide application in X-ray and neutron diffraction imaging. The object transmission functions are successfully retrieved from the lensless Fourier transform frequency spectrums, which are obtained in experiment using incoherent light. Using the error reduction algorithm and the input-output algorithm integrated with over sampling theory,the amplitude distribution function of amplitude-only object and the phase distribution function of pure-phase object are retrieved successfully. The influence of the noise of Fourier transform frequency spectrum in the experiment on the retrieval result is also discussed..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 27, Issue 11, 2075 (2007)
Spectroscopy
A Spectrometer Method for Determining Thickness of Quartz Plate Along the Crystal Axis
[in Chinese], [in Chinese], [in Chinese], and [in Chinese]
A spectrometer method for determining the thickness of quartz plate along the crystal axis is presented based on the optical rotatory dispersion effect of the quartz. Its operating principle is analyzed by means of matrix formulation, and the result indicates that the thickness of the quartz plate along the crystal axiA spectrometer method for determining the thickness of quartz plate along the crystal axis is presented based on the optical rotatory dispersion effect of the quartz. Its operating principle is analyzed by means of matrix formulation, and the result indicates that the thickness of the quartz plate along the crystal axis will be exactly obtained by accurate judgment of the transmission curve of a quartz plate sandwiched between two crossed polarizers. The error in the experiment is analyzed and it is found that the measuring accuracy will be improved by choosing longer wave band, lower scan speed, shorter response time and smaller slit width. At the same time, the theoretical analysis proves that the measuring accuracy of this method is higher than the digital micrometer's. In the end, two quartz plates with different thicknesses are measured by three different methods, respectively. It is shown that the accuracy of the tested thickness is 0.1 μm and is in good agreement with the theoretical prediction..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 27, Issue 11, 2082 (2007)
Determination of the Absolute Absorption Cross Section of Oxygen Forbidden Transition by Cavity Ring down Spectroscopy
[in Chinese], [in Chinese], [in Chinese], [in Chinese], and [in Chinese]
Cavity ring down spectroscopy (CRDS) not only has high sensitivity, but also can measure the absolute absorption of the sample gas. The decay time of the oxygen molecule at 17266.090 cm-1 is recorded at system's limiting vacuum and other different pressure of oxygen filled in the cavity. Therefore, the lifetime of Cavity ring down spectroscopy (CRDS) not only has high sensitivity, but also can measure the absolute absorption of the sample gas. The decay time of the oxygen molecule at 17266.090 cm-1 is recorded at system's limiting vacuum and other different pressure of oxygen filled in the cavity. Therefore, the lifetime of the empty cavity is obtained to be 2.9174 ms by approaching method, and the absolute absorption cross section of RQ(5) ro-vibrational line of the (3, 0) band in the triple forbidden transition b1∑+g–X3∑-g of O2 is determined to be 1.4998(±0.0967)×10-26 cm2, which is in good agreement with previous estimation, by employing continuous wave CRDS. Additionally, the reflectance of the two identical cavity mirrors, obtained by the approached empty cavity lifetime, is determined to be 99.989 (±0.001)%, which is more accurate than usual method, and the equivalent absorption length is prolonged by a factor of about 9090 in our experimental condition..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 27, Issue 11, 2087 (2007)
X-Ray Optics
Inherent Spatial Resolution of Mercuric Iodide by Monte Carlo Simulation
[in Chinese], [in Chinese], [in Chinese], [in Chinese], and [in Chinese]
Mercuric iodide (HgI2), as a semiconductor detecting material directly absorbing X-ray, its inherent spatial resolution has been investigated for the medical diagnosis X-ray energy. The Monte-Carlo simulation is performed with an infinitesimal pencil-beam of X-ray incident on the HgI2 slab to determine its modulation tMercuric iodide (HgI2), as a semiconductor detecting material directly absorbing X-ray, its inherent spatial resolution has been investigated for the medical diagnosis X-ray energy. The Monte-Carlo simulation is performed with an infinitesimal pencil-beam of X-ray incident on the HgI2 slab to determine its modulation transfer function(MTF). The simulation is based on the user code DOSRZnrc of the latest version of the EGSnrc, and these effects on HgI2 spatial resolution by the reabsorptions of fluorescence and scattered photons, expanded ranges of fast photoelectrons and off-axis incident angle, are considered and the simulated results accord with the literature analytic results well. The simulation results show that the ranges of primary fast photoelectrons and off-axis incident angle can affect the spatial resolution of the material greatly and the spatial resolution is sensitive to the incident X-ray energy since the modulation transfer function (MTF) decreases greatly with the increasing of X-ray energy, which however depends hardly on the thickness of the film. Compared with amorphous Se, HgI2 has a higher inherent spatial resolution, especially for above 50 keV X-ray energy. When fMTF=0.5, for X-ray photon energy of 20 keV, 50 keV and 100 keV, the inherent spatial resolutions of HgI2 and amorphous Se are 390 lp/mm, 170 lp/mm,52 lp/mm and 390 lp/mm, 80 lp/mm, 22 lp/mm, respectively..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 27, Issue 11, 2091 (2007)
A Fast Online Method to Measure and Calculate the Apple's Cubage Based on X-Ray Image
[in Chinese], [in Chinese], [in Chinese], and [in Chinese]
By using the direct ratio between the minus exponential of every gray value of two-dimensional X-ray image and the thickness of the slice, the attenuation coefficient of the apple was calculated on the condition of the invariable experimental parameters. The mathematic model to predict apple cubage was established, andBy using the direct ratio between the minus exponential of every gray value of two-dimensional X-ray image and the thickness of the slice, the attenuation coefficient of the apple was calculated on the condition of the invariable experimental parameters. The mathematic model to predict apple cubage was established, and the cubage of the apple was predicted. The result of the experiment testified the exponential relation between the attenuation of the X-ray energy and the thickness of the apple slice, the regression correlation coefficients for calibration is 0.9932, and the average attenuation coefficient is 0.0114. The regression model was obtained with the correlation coefficient for calibration and prediction coefficient of 0.9809 and 0.9203, respectively between the actual value and predicted value of apple cubage. The mathematic model could calculate the cubage of the apple reliably and credibly..
Acta Optica Sinica
- Publication Date: Jun. 19, 2020
- Vol. 27, Issue 11, 2096 (2007)
© Copyright 2018-2021 | Chinese Laser Press. All Rights Reserved 沪ICP备15018463号-20