Contents
2005
Volume: 25 Issue 3
30 Article(s)
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Atmospheric Optics and Oceanic Optics
The Correction of Short-Range Laser Lidar Returns with Fitting to Lidar Range-Adjusted Power
[in Chinese], [in Chinese], [in Chinese], [in Chinese], and [in Chinese]
A new method for correcting scattering laser lidar data is reported. Firstly, in the insufficient overlapping range between the transmitting laser beam and the field of view of the receiving telescope, the logarithmic range-adjusted power curve S(r) is fitted with conic, and the difference between the conic and the oriA new method for correcting scattering laser lidar data is reported. Firstly, in the insufficient overlapping range between the transmitting laser beam and the field of view of the receiving telescope, the logarithmic range-adjusted power curve S(r) is fitted with conic, and the difference between the conic and the original S(r) in the short range is gotten. Secondly, the slope of curve S(r) in short range is obtained by fitting the curve S(r) in the long range on the assumption of an almost homogenous atmosphere. At last, by adding difference signal to the fitting line of S(r) in the short ange, the short-range S(r) is corrected. The correction results are close to the real atmospheric conditions..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 25, Issue 3, 289 (2005)
Coherence and Statistical Optics
Spectrum Properties of Partially Coherent Beams in Turbulent Atmosphere
[in Chinese], and [in Chinese]
The spectrum properties of partially coherent beams propagating in turbulent atmosphere are studied. Basing on the extended Huygens-Fresnel principle, an analytical propagation formula for the cross-spectral density of partially coherent beams in turbulent atmosphere is derived. The degree of spatial coherence and specThe spectrum properties of partially coherent beams propagating in turbulent atmosphere are studied. Basing on the extended Huygens-Fresnel principle, an analytical propagation formula for the cross-spectral density of partially coherent beams in turbulent atmosphere is derived. The degree of spatial coherence and spectral shift of partially coherent beams through turbulent atmosphere are analyzed by using the derived formula. The results show that the spectrum of the partially coherent beam on axis in turbulent atmosphere is blueshifted in the beginning, the mount of the shift firstly increases, afterwards decreases, and finally a red shift appears with the increase of propagation distance. The lower the beam coherence is, the farther propagation distance is needed when red shift appears. At first the degree of spatial coherence increases, then decreases and approaches to zero finally. Comparing with the propagation of the partially coherent beam in free space, the atmospheric turbulence has small influence on the spectrum properties of the partially coherent beam in a short distance propagation, while has a strong influence on it in a sufficient long distance propagation..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 25, Issue 3, 293 (2005)
Fiber Optics and Optical Communications
The Birefringence Characteristics of High Numerical Aperture TwinCore Fiber
[in Chinese], [in Chinese], [in Chinese], [in Chinese], and [in Chinese]
We explore the birefringence characterization of twin??core fiber (TCF) with high numerical apertures. Firstly the super cell lattice orthogonal function method and mode couple theory are used to analyze the geometrical birefringence of the TCF, then we make comparison of the results that calculated from the two differWe explore the birefringence characterization of twin??core fiber (TCF) with high numerical apertures. Firstly the super cell lattice orthogonal function method and mode couple theory are used to analyze the geometrical birefringence of the TCF, then we make comparison of the results that calculated from the two different methods. The results show that the geometrical birefringence of TCF is not enough high even when the cores are touching; the maximum geometrical birefringence is only at 10-5. The maximum geometrical birefringence of twin elliptical core fiber can reach 10-4, which is calculated from super cell lattice orthogonal function method. High concentration of germanium is needed to keep high NA. We calculate the stress birefringence of the TCF with high NA in the area of assembling of light power, which approximates to 10-4. The twin??core erbium doped fiber (TCEDF) with well polarization maintaining performance is designed and fabricated, the geometrical parameters and refractive index distribution of the twin??core fiber are measured and analyzed, and the birefringence coefficient of twin-core fiber reaches 8.4×10-5. TCEDF with high NA can be used as polarization maintaining EDF that is a key component in optical fiber lasers with single polarization output..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 25, Issue 3, 297 (2005)
Influences of Input Optical Pulses on Switching Window of UNI
[in Chinese], [in Chinese], [in Chinese], [in Chinese], and [in Chinese]
Influences of input optical pulses including the control pulse and probe pulse on the switching window of ultrafast nonlinear interferometer (UNI) are studied by numerical simulation and experiment. The power and width of input optical pulses are adjusted in the process of numerical simulation. In the beginning, the hiInfluences of input optical pulses including the control pulse and probe pulse on the switching window of ultrafast nonlinear interferometer (UNI) are studied by numerical simulation and experiment. The power and width of input optical pulses are adjusted in the process of numerical simulation. In the beginning, the higher the powers of control pulse and probe pulse and the narrower the widths of them, the better the shape of the switching window. There are optimal values of the power of them for the best shape of the switching window. If the power of control pulse continues to increase, the top of the switching window inclines and the shape of the switching window gets worse. Similarly, if the power of probe pulse continues to increase, the extinction ratio of switching window would decrease. In the experiment of 10 Gb/s UNI, the continuous light is used to replace the probe pulse in order to observe the switching window. By changing the powers of control pulse and the continuous light, the results of simulation are verified. The experiment demonstrates that the high power and the narrow width of control pulse and the optimal power of continuous light should be selected. The result of experiment is quite similar to the simulation..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 25, Issue 3, 302 (2005)
A Novel Fiberg Grating Sensing and Demodulating System with Temperature Compensation
[in Chinese], [in Chinese], [in Chinese], [in Chinese], [in Chinese], and [in Chinese]
The temperature characteristics of triangular fiber Bragg gratings have been studied theoretically and experimentally. The results show that the rate of resonant wavelength with temperature of the triangular fiber Bragg gratings is the same as that of ordinary fiber Bragg gratings, and the spectral shape of the gratingThe temperature characteristics of triangular fiber Bragg gratings have been studied theoretically and experimentally. The results show that the rate of resonant wavelength with temperature of the triangular fiber Bragg gratings is the same as that of ordinary fiber Bragg gratings, and the spectral shape of the grating can be kept without being affected by temperature. For the characteristics, a novel strain sensing and demodulating system with temperature compensation is designed. In the system, the wavelength code of strain is converted into the signal intensity, and the ratio of the signal intensity and the referent light intensity is used as the measuring value of strain. Theoretical and experimental researches indicate that the strain is proportional to the measurement value, and the system has the temperature compensation property. At three different temperature conditions, the strain test results of the cantilever experiments show that the measurement error of strain is less than 6 micro-strain /℃. For adopting the ratio of the signal intensity and the referent light intensity as the measuring value of strain, it avoids the effect to the test results coming from the flatness and fluctuating of the broad band light source..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 25, Issue 3, 307 (2005)
Image Processing
Study on Approach of Detection for Video Image Based on Decomposable Markov Network
[in Chinese], [in Chinese], and [in Chinese]
The concept and method of decomposable Markov network (DMN) are sdudied, and the role of DMN in data mining from sequence images is analyzed. The construct of DMN is straight utilized as the evidence of inference or decision for problem solution and enlargement of application possibility in DMN. For example of the factThe concept and method of decomposable Markov network (DMN) are sdudied, and the role of DMN in data mining from sequence images is analyzed. The construct of DMN is straight utilized as the evidence of inference or decision for problem solution and enlargement of application possibility in DMN. For example of the factual video images with traffic rule violation, we deeply investigate several graininess (nodes) which are used in constructing DMN between video images, assess its applicability for our problem, and detect abnormality in them by analyzing construct of DMN for finding a interesting mode. It is showed that the method is feasible and effective according to the result of simulation. The researches indicate that the DMN may apropos reveal abstract adjacent relations existing in data, has capabilities of showing knowledge and logic reasoning, and also is important method of pattern recognition..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 25, Issue 3, 312 (2005)
Research on Non-Contact Method of Capturing Iris Image and Extracting Feature
[in Chinese], [in Chinese], [in Chinese], and [in Chinese]
A new method for iris recognition is presented, which can help users to get correct position and accomplish non-contact capture by self-aiming. The experiments on extracting feature from iris texture are carried out, and the feasibility and efficiency of this method are verified. The special illumination is designed foA new method for iris recognition is presented, which can help users to get correct position and accomplish non-contact capture by self-aiming. The experiments on extracting feature from iris texture are carried out, and the feasibility and efficiency of this method are verified. The special illumination is designed for the purpose of assisting users to focus their eyes on the proper position. A piece of pellicle mirror is placed in front of the camera lens to help users to observe the eyes' image and ensure that the eyes are in the camera visual field. Thus image data that meet the requirement of iris recognition can be obtained. The two-dimensional Gabor wavelet theory is adopted for extracting feature from iris texture. Feature matching experiments are made by counting the amount of the equal flag bits of two iris images..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 25, Issue 3, 319 (2005)
Imaging Systems
Analysis of Noise Characteristics in an Optical Coherence Tomographic System
[in Chinese], [in Chinese], [in Chinese], [in Chinese], [in Chinese], and [in Chinese]
Optical coherence tomography (OCT) is a high resolution imaging technology developed in the recent years and based on many cutting-edge sciences and techniques. The principle is introduced, the OCT system based on time linear modulation and Michelson interferometer is given with its initial experimental results. The opOptical coherence tomography (OCT) is a high resolution imaging technology developed in the recent years and based on many cutting-edge sciences and techniques. The principle is introduced, the OCT system based on time linear modulation and Michelson interferometer is given with its initial experimental results. The optical spectra of the light source and uneven scanning speed of reference delay line are emphasized by the simulation and experimental research. Using the FFT method, the analysis of parameter properties based on experimental results and their influence on practical coherence tomography is presented from the point of view of engineering designing, therefore the improved method is obtained..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 25, Issue 3, 324 (2005)
Fast Photoacoustic Imaging Based on Multi-Element Linear Transducer Array
[in Chinese], [in Chinese], [in Chinese], [in Chinese], and [in Chinese]
A fast photoacoustic (PA) imaging system based on multi-element linear transducer array and phase-controlled focus method was developed and tested on phantoms. A Q-switched Nd∶YAG laser operating at 532 nm and pulse width of 7 ns was used in our experiment as thermal source. The multi-element linear transducer array coA fast photoacoustic (PA) imaging system based on multi-element linear transducer array and phase-controlled focus method was developed and tested on phantoms. A Q-switched Nd∶YAG laser operating at 532 nm and pulse width of 7 ns was used in our experiment as thermal source. The multi-element linear transducer array consists of 320 elements. By phase-controlled focus method, 64 signals, one of which gathered by 11-group element, make up an image. Phantom experimental results can reflect the distribution of the optical absorption correctly. Compared to other existing technology and algorithm, the PA imaging based on transducer array was characterized with speediness and convenience. It can provide a new approach for tissue functional imaging at vivo, and may have potentials in developing an appliance for clinic diagnosis..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 25, Issue 3, 331 (2005)
Instrumentation, Measurement and Metrology
Wave Front Reconstruction from Shearing Interferograms Using Least Square Fitting
[in Chinese], [in Chinese], [in Chinese], and [in Chinese]
Authors propose a novel technique to reconstruct two-dimensional wave front from two difference wave fronts that are measured in shearing interferometers. Firstly, two one-dimensional wavefront estimates are computed using Fourier transform. The two-dimensional wave front distribution is then derived by use of least sqAuthors propose a novel technique to reconstruct two-dimensional wave front from two difference wave fronts that are measured in shearing interferometers. Firstly, two one-dimensional wavefront estimates are computed using Fourier transform. The two-dimensional wave front distribution is then derived by use of least square fitting. The proposed method is applicable to cases in which the shear amount is larger than one sampling interval, and can alleviate the limitation on the shear amount imposed by conventional algorithm. Investigation into the influences of shear amount and noise level on reconstruction accuracy is made, and comparisons with other methods are also provided. Numeric simulations to confirm the proposed algorithm are carried out, and corresponding analyses and discussions are given. The results show that the method is relatively immune to noises and is promising in practical shearing interferomertry..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 25, Issue 3, 335 (2005)
Interferometer for Endface Geometry Parameter Measurement of Optical Fiber Connector
[in Chinese], [in Chinese], [in Chinese], [in Chinese], and [in Chinese]
An interferometer for measuring endface geometry parameters of optical fiber connector with high accuracy is reported. The endface topography of the optical fiber connector and the coordinates of the center of the fiber core are obtained. The endface geometry parameters, which have a great effect on the performance of An interferometer for measuring endface geometry parameters of optical fiber connector with high accuracy is reported. The endface topography of the optical fiber connector and the coordinates of the center of the fiber core are obtained. The endface geometry parameters, which have a great effect on the performance of optical fiber connector, are calculated. The interferometer is compact and easy to use. It can be used to measure the endface geometry parameters of physical contact, angle physical contact and other kinds of optical fiber connector. Actual measurements show that the interferometer has a good repeatability. The measurement accuracy of the interferometer is at the same level as that of the Dorc's ZX-1 mini PMS interferometer and the Norland's NC3000 interferometer. The interferometer has passed the test performed by the National Center of Measurement and Test for East China..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 25, Issue 3, 341 (2005)
A Testing Method for a MOEMS Optical Switch Using CCD
[in Chinese], [in Chinese], [in Chinese], [in Chinese], [in Chinese], [in Chinese], and [in Chinese]
The movement status of the deivce needs to be determined accurately under the driven conditions in the design and fabrication of the optoelectronic devices based on the micro-opto-electro-mechanical systems (MOEMS). Because of the limitation of geometrical dimensions, there are some difficulties in accurate measurementThe movement status of the deivce needs to be determined accurately under the driven conditions in the design and fabrication of the optoelectronic devices based on the micro-opto-electro-mechanical systems (MOEMS). Because of the limitation of geometrical dimensions, there are some difficulties in accurate measurement on the driven conditions for MOEMS optical switch. This paper presents an optical method for the measurement of the angular rotation of the cantilever beam on the optical switch. Based on the theoretical analysis, the relations of the angular rotation and the measurable parameters are given, and the optimized results of the measurable parameters are performed. The measure error is less 10% and the experimental results obtained demonstrate that the feasibility of the proposed method to be used for evaluating the driven conditions of the MOEMS optical switch..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 25, Issue 3, 346 (2005)
Lasers and Laser Optics
Deformable Mirror Used for Spectral Phase Compensation in 1 kHz Ti∶Sapphire Femtosecond Laser
[in Chinese], [in Chinese], [in Chinese], [in Chinese], and [in Chinese]
The authors demonstrated the spectral phase aberration compensation of a 1 kHz Ti∶sapphire femtosecond laser system using a deformable mirror by stretching the spectrum of the laser beam. The authors set up a set of measurement and compensation system using a deformable mirror and a spectral phase interferometry for diThe authors demonstrated the spectral phase aberration compensation of a 1 kHz Ti∶sapphire femtosecond laser system using a deformable mirror by stretching the spectrum of the laser beam. The authors set up a set of measurement and compensation system using a deformable mirror and a spectral phase interferometry for direct electric-field reconstruction (SPIDER) instrument in a 1 kHz Ti∶sapphire femtosecond laser. The experimental result showed that the spectral phase aberration of the laser was compensated well and the beam quality was improved. It is a simple and efficient method in adaptive optics using the deformable mirror to compensate the spectral phase aberration..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 25, Issue 3, 351 (2005)
Electro Optically Cavity-Dumped Laser-Diode Pumped Mode-Locked Nd∶YAG Laser with a Semiconductor Saturable Absorber Mirror
[in Chinese], [in Chinese], [in Chinese], [in Chinese], [in Chinese], [in Chinese], [in Chinese], [in Chinese], and [in Chinese]
An electro optically cavity-dumped laser diode-pumped mode-locked Nd∶YAG laser with a semiconductor saturable absorber mirror is reported. In the experiment tha authors employed a simple straight cavity to study the cavity dumping of the mode-locked laser. The generation, amplification and dumping of the short pulses wAn electro optically cavity-dumped laser diode-pumped mode-locked Nd∶YAG laser with a semiconductor saturable absorber mirror is reported. In the experiment tha authors employed a simple straight cavity to study the cavity dumping of the mode-locked laser. The generation, amplification and dumping of the short pulses were completed in this simple setup. With 5 W pump power the authors obtained the 11 ps single mode-locked pulse output and 200 ns Q-switched pulse output, and the single pulse energy is 30 nJ and the repetition rate is 10 Hz. The single pulse energy of cavity dumped pulse is about 15 times that of the continuous mode-locked pulse. The effect of the high voltage on the electro optical crystal and the polarization of polariser on the mode-locked pulse and the Q-switched pulse are discussed..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 25, Issue 3, 356 (2005)
Study of the Low Gain Excimer Laser Optimum Transmission
[in Chinese], [in Chinese], and [in Chinese]
For the laser system performance, the resonator optimum transmission is of great important. The optimum transmission of low gain, broadband-pulsed excimer laser is closely relative to the gain duration, which is caused by its pump pulse. The transition behavior of excimer laser is simulated based on the rate equations For the laser system performance, the resonator optimum transmission is of great important. The optimum transmission of low gain, broadband-pulsed excimer laser is closely relative to the gain duration, which is caused by its pump pulse. The transition behavior of excimer laser is simulated based on the rate equations of four-level laser energy systems. In terms of reasonable approximation, an analytical description for the optimum transmission of the low gain,pulsed excimer laser is developed. The uniform optimum transmission condition in the different gain duration is given, and the optimum transmission as a function of net gain is analyzed. The optimum transmission of low gain, broadband-pulsed excimer laser is fundamentally different from the continuous wave (CW) lasers, and it depends on the relation of gain duration and photon lifetime in the resonator, these above mentioned analytical results are approved by the corresponding experimental results..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 25, Issue 3, 359 (2005)
Materials
Spectroscopic Properties of Er3+-Doped TeO2-WO3-Na2O Glasses for Ion-Exchanged Waveguide Devices
[in Chinese], [in Chinese], [in Chinese], and [in Chinese]
A New Er3+-doped TeO2-WO3-Na2O glass for ion-exchanged waveguide devices has been fabricated and characterized. The measured absorption and emission spectra of the glass were analyzed by the Judd-Ofelt and McCumber theories. The intensity parameters are Ω2=7.01×10-20 cm2, Ω2=1.80×10-20 cm2, Ω2=1.03×10-20A New Er3+-doped TeO2-WO3-Na2O glass for ion-exchanged waveguide devices has been fabricated and characterized. The measured absorption and emission spectra of the glass were analyzed by the Judd-Ofelt and McCumber theories. The intensity parameters are Ω2=7.01×10-20 cm2, Ω2=1.80×10-20 cm2, Ω2=1.03×10-20 cm2. The glass has high and broadband absorption and stimulated emission cross-sections at 1.5 μm. The maximum emission cross-section is 0.91×10-20 cm2 at 1.533 μm, and a broad 1.5 μm emission spectrum of 65 nm full width at half maximum (FWHM) is demonstrated. Emission properties for 4I13/2→4I15/2 transition of Er3+ in different glasses are compared with each other. It is indicated that Er3+-doped TeO2-WO3-Na2O glasses will be a promising candidate for broadband ion-exchanged waveguide devices..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 25, Issue 3, 364 (2005)
Forster Energy Transfer in Organic Blend Thin-Film
[in Chinese], [in Chinese], [in Chinese], [in Chinese], and [in Chinese]
The emission color of organic electroluminescent devices can be tuned by doping the active layer with certain dyes or other fluorescent molecules. We demonstrate the realization of green PLED by doping a blue light emitting polymer poly(N-vinyl-carbazole) (PVK) with a novel green light emitting molecule tetra-methylestThe emission color of organic electroluminescent devices can be tuned by doping the active layer with certain dyes or other fluorescent molecules. We demonstrate the realization of green PLED by doping a blue light emitting polymer poly(N-vinyl-carbazole) (PVK) with a novel green light emitting molecule tetra-methylester of perylene-3,4,9,10-tetracarboxylicacid (TMEP). At TMEP 0.01 (mass ratio) doping concentration, excited by 295.5 nm, photoluminescence clearly show two emission peaks belonging to PVK and TMEP. For TMEP concentrations between 0.05～0.10 (mass ratio) the photoluminescence (PL) and the electroluminescence (EL) spectrum of the TMEP/PVK blend are almost dominated by TMEP emission because of an excitation energy transfering from PVK to TMEP. The reason for the efficient energy transfering can be explained by the efficient F??rster energy transfering from PVK to TMEP. PL spectra redshift with the increasing concentration of TMEP is due to the excimer formation. The difference between PL spectra of TMEP solution and PL spectra of TMEP solid film confirms the formation of excimer..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 25, Issue 3, 369 (2005)
Simulation on the Optical Properties for the PbWO4 Crystal Containing Lead Vacancy
[in Chinese], [in Chinese], and [in Chinese]
In order to study the optical properties of the PWO crystal containing V2-Pb, the optimization of the lattice structure containing V2-Pb has been performed by using LAPW+lo method and the conjugate gradient method. All other calculations are performed on the basis of the lattice structure being optimized. The electroniIn order to study the optical properties of the PWO crystal containing V2-Pb, the optimization of the lattice structure containing V2-Pb has been performed by using LAPW+lo method and the conjugate gradient method. All other calculations are performed on the basis of the lattice structure being optimized. The electronic structure, dielectric function, complex refractive index and absorption spectra for the perfect PbWO4(PWO) crystal and the PWO crystal containing V2-Pb have been calculated by using LAPW+lo method. The peaks of the absorption spectra corresponding which electronic transitions have been studied. The calculated results indicate that the perfect PWO crystal does not have absorption band in the visible and near-ultraviolet region; however, the PWO crystal containing V2-Pb has two absorption bands in this region. The two absorption bands can be well fitted into four Gaussian-shape bands peaking at 350 nm, 405 nm, 550 nm and 670 nm. This predicates that the 350 nm, 420 nm, 550 nm and 670 nm absorption bands are related to the existence of the V2-Pb in PWO crystal..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 25, Issue 3, 373 (2005)
Medical Optics and Biotechnology
The Spatially Resolved Scattered Reflection of Three-Layered Matched Media Diffusion Equation in the Steady-State
[in Chinese], [in Chinese], [in Chinese], and [in Chinese]
If we can apply the diffuse equation to analyze and decide optical properties of superficial biological tissue, we can determine if the pathological changes occur in vivo, thus we can realize the noninvasive in vivo measurement. Currently, a semi-infinite media photon migration model and a two-layered turbid medium modIf we can apply the diffuse equation to analyze and decide optical properties of superficial biological tissue, we can determine if the pathological changes occur in vivo, thus we can realize the noninvasive in vivo measurement. Currently, a semi-infinite media photon migration model and a two-layered turbid medium model are utilized widely. But actually, there is a multi-layered turbid medium in tissue. According to the diffusion equation, employing the extrapolated boundary condition, we analyze the diffusion of photons of a three-layered matched medium and deduce the solution of Green's function. Through comparing the spatially resolved reflectance between the solution of three-layered matched media diffusion equation and Monte-Carlo simulation, we find our solution of a three layered matched media theory not only accords with a two-layered turbid medium model which is solved by A. Kienle, but also agrees with Monte-Carlo simulation..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 25, Issue 3, 377 (2005)
Nonlinear Optics
Study of Polarized Light Properties of Stimulated Raman Scattering in the Birefringence Fibers
[in Chinese], [in Chinese], [in Chinese], and [in Chinese]
The polarized light properties of stimulated Raman scattering (SRS) in elliptical core optical fiber is systematically. In experiments, eight orders of Stokes lines and two orders of anti-Stokes spectra are observed and some parameters are analyzed such as the polarization, Raman frequency-shift of each-order Stokes spThe polarized light properties of stimulated Raman scattering (SRS) in elliptical core optical fiber is systematically. In experiments, eight orders of Stokes lines and two orders of anti-Stokes spectra are observed and some parameters are analyzed such as the polarization, Raman frequency-shift of each-order Stokes spectra under different polarization state of pump light, and the experience formula are also provided. The results are in good agreement with the experimental figures. Experiments indicate that each-order Stokes spectra polarization state of stimulated Raman scattering in the birefringence optical fiber is related not only with Raman medium but also with pump light polarization state. The influence of pump light polarization state on low-order Stokes frequency-shift is lower but higher on the high-order Raman Stokes frequency shift fluctuation..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 25, Issue 3, 382 (2005)
The Effect of Third-Order Nonlinear Interaction on High-Efficiency Third Harmonic Generation Conversion
[in Chinese], [in Chinese], [in Chinese], [in Chinese], [in Chinese], and [in Chinese]
A theoretical analysis is presented for conversion of third-harmonic generation (THG) in KDP crystal for type Ⅰ/Ⅱ angle-detuning scheme of high-intensity laser. Taking into account the the third-order nonlinear effects, transverse walk-off and diffraction, mostly the effects of third-order nonlinear χ(3) interactions oA theoretical analysis is presented for conversion of third-harmonic generation (THG) in KDP crystal for type Ⅰ/Ⅱ angle-detuning scheme of high-intensity laser. Taking into account the the third-order nonlinear effects, transverse walk-off and diffraction, mostly the effects of third-order nonlinear χ(3) interactions on the frequency conversion and the phase matching condition are discussed. A split-step algorithm based on the fast Fourier transform (FFT) and a Runge-Kutta (R-K) integrator is used. The results show that the third-order nonlinear effect decreases the tripling efficiencies and increases the modulate depth of the output intensity of 3ω radiation. However, adjusting the angular detuning (Δθs) can avoid effectively the third-order nonlinear effects..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 25, Issue 3, 387 (2005)
OPTICAL DATA STORAGE
Fabrication of a Diffractive Image Lithographic System for Optical Storage
[in Chinese], [in Chinese], [in Chinese], [in Chinese], [in Chinese], [in Chinese], and [in Chinese]
A novel digital laser lithographic system has been fabricated for storing optical information on the diffractive optical variable image device (DOVID). The digital input patterns on spatial light modulator (SLM) are imaged into the micro-images in the recording plane by a two tele-centric optical projection system withA novel digital laser lithographic system has been fabricated for storing optical information on the diffractive optical variable image device (DOVID). The digital input patterns on spatial light modulator (SLM) are imaged into the micro-images in the recording plane by a two tele-centric optical projection system with large reduction ratio. The micro-images are modulated by the interferential fringes with the spatial frequency range from 500～1200 lp/mm, which are generated by a grating interferential optical head in the lithographic system. The experimental results recorded on the photoresist plate show that the information storage density can be achieved over 3.7 Mbit/cm2 in one direction storage. The angle rotating multiplexing optical storage can be automatically realized by inputting multiple patterns needed to be stored, at the meantime, changing the direction and spatial frequency of interferential fringes. The optical storage lithographic system is useful in the fields of optical security and fabrication of diffraction optical variable image devices..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 25, Issue 3, 392 (2005)
Effects of Monomers and Binders in the Photopolymer on Holographic Data Storage Properties
[in Chinese], [in Chinese], [in Chinese], and [in Chinese]
Effects of monomers and binders in the photopolymer on holographic storage properties are studied. Under the same initiator conditions, diffraction efficiency of photopolymer with an acrylamide monomer is significantly larger than that of acrylic acid and N-hydroxymethylacrylamide monomers, respectively. N-hydroxymethyEffects of monomers and binders in the photopolymer on holographic storage properties are studied. Under the same initiator conditions, diffraction efficiency of photopolymer with an acrylamide monomer is significantly larger than that of acrylic acid and N-hydroxymethylacrylamide monomers, respectively. N-hydroxymethylacrylamide can improve optical quality, reduce scattering intensity, and increase the shelf life time of the films. Compared with polyvinylpyrrolidone (PVP), polymerization degree of monomer in the polyvinylalcohol (PVA) is higher. Diffraction efficiency and energetic sensitivity are larger in the PVA with a high average molecular weight than in the PVA with low average molecular weight. The PVA with a high average molecular weight can be used to prepare thick films, and it is an important factor to realize the mass capacity of holographic data storage..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 25, Issue 3, 396 (2005)
Optical Design and Fabrication
A New Polishing Technology For Large Diameter and Deep Aspherical Mirror
[in Chinese], [in Chinese], [in Chinese], [in Chinese], [in Chinese], [in Chinese], [in Chinese], and [in Chinese]
Stressed lap polishing technology is a new large and deep asphericity astronomical polishing mirror. Because the diameter of astronomical mirror is larger and larger, the asphericity is deeper and deeper, we develop the stress lap technology, it can actively deform the lap surface to become an off-axis asphere accordinStressed lap polishing technology is a new large and deep asphericity astronomical polishing mirror. Because the diameter of astronomical mirror is larger and larger, the asphericity is deeper and deeper, we develop the stress lap technology, it can actively deform the lap surface to become an off-axis asphere according to different lap position on mirror surface and different angle of lap. The curvature is different not only on different position, but also on different direction, so the classical large polishing lap cannot keep the lap surface with the aspherical mirror surface when it moves and spins on the mirror surface. The classical small polishing tool not only can get high frequency error on the mirror surface, but also has slow polishing speed. The stressed lap is just enough to solve these problems. Compared with traditional polishing methods, it has high polishing speed and natural smooth. It is computer-controlled polishing technology, using it the authors can polish a deep aspherical mirror just like polish a spherical mirror. This paper introduce our stressed lap and how to apply it to ??910 mm, with F/2 paraboloidal mirror and its testing result. Next step, the authors will develop this technology to polish the off-axis aspherical segment..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 25, Issue 3, 402 (2005)
OPTOELECTRONICS
The Fabrication of Narrow Spectrum LED by Employing Asymmetry One-Dimensional Photonic Crystal
[in Chinese], [in Chinese], [in Chinese], and [in Chinese]
The transmission of light waves through a perturbed one-dimensional (1D) photonic band gap structures (PBGS) which was constructed by stacking a number of GaAlAs/AlAs unit cells, has been investigated. Because of the interruption to the stack periodicity of the unit cells, the electromagnetic density of modes (DOM) of The transmission of light waves through a perturbed one-dimensional (1D) photonic band gap structures (PBGS) which was constructed by stacking a number of GaAlAs/AlAs unit cells, has been investigated. Because of the interruption to the stack periodicity of the unit cells, the electromagnetic density of modes (DOM) of the photonic crystals was changed, so that the transmission of the light waves changed. And the DOM and the transmission mode were calculated and simulated by the popular density calculation method and the characteristic matrix. It is found that the asymmetric structures are more profitable compared with symmetric structure in applications. The asymmetric 1D PBGS was realized by the MOCVD method. The full width at half maximum (FWHM) narrowed to 3.1 nm, inspired at 20 mA, which is better than RCLED. And the edge emission was also observed..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 25, Issue 3, 408 (2005)
Quantum Optics
Double-Well Surface Magneto-Optical Trap for Neutral Atoms and Its Potential Applications
[in Chinese], and [in Chinese]
A novel scheme is proposed to form double-well magneto-optical surface trap for cold atoms using double U-shaped current-carrying wires. It shows that the double-well magnetic trap proposed here could be continuously transfered into a single one by adjusting the current in an inner U-shaped wire from a suitable value tA novel scheme is proposed to form double-well magneto-optical surface trap for cold atoms using double U-shaped current-carrying wires. It shows that the double-well magnetic trap proposed here could be continuously transfered into a single one by adjusting the current in an inner U-shaped wire from a suitable value to zero, and vice versa. The spatial distributions of magnetic fields from double U-shaped current-carrying wires layout and their gradients are calculated and analyzed. It is found that the magnetic field gradient near the center of each magnetic trap generated by the double U-shaped wires is about 1.5×10-3～2.5 ×10-3T/cm when the currents in the double U-shaped wires are both equal to 600 A and the inhomogeneous bias magnetic field in z-direction is -4.0 ×10-3T. By associating with 3D optical Molasses beams used in the usual magneto-optical trap (MOT), the double-well magneto-optical surface trap can be used to realize double-well MOT near the surface of wire plane. Under the approximation of low intensity, a cold atomic sample with a captured number of ～106 atoms at a temperature of about 270 μK can be obtained in each 85Rb atomic MOT. Since each MOT in two-species MOT can be prepared independently, the controllable double-well trap can be used to study the cold collisions between two different atomic samples..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 25, Issue 3, 412 (2005)
The Statistics of Photon of Entangled Fields Interacting with a Three-Level Atom in Kerr Medium
[in Chinese], and [in Chinese]
The statistic properties of photon in the system of a two-mode entangled coherent fields interacting with a V-type three-level atom in Kerr medium are investigated by solving Schr??dinger equation and numerical calculations. The effects on the statistic properties of photon induced by the degree of entanglement of the The statistic properties of photon in the system of a two-mode entangled coherent fields interacting with a V-type three-level atom in Kerr medium are investigated by solving Schr??dinger equation and numerical calculations. The effects on the statistic properties of photon induced by the degree of entanglement of the two-mode entangled coherent fields, the coupling degree of the Kerr medium with the light field, the mean photon numbers and the ground state probability amplitude of atomic initial state are analyzed. The results indicate that the influence of the degree of entanglement of the two-mode entangled coherent fields on the statistic properties of photon isn't noticeable. The enhancing of Kerr effect results in the increase of the oscillating frequency of the time evolution curve of statistic properties of photon and the decrease of the oscillating amplitude of the curve. When the mean photon numbers of the mode 1 remain unchanged and the mean photon numbers of the mode 2 decreased, the oscillating amplitude of the curve increases..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 25, Issue 3, 419 (2005)
Experimental Scheme of Secure Plaintext Transmission with Quantum Direct Communication
[in Chinese], [in Chinese], and [in Chinese]
“Ping-pong” protocol is a novel secure deterministic quantum communication protocol. Based on an entangled pair of qubit, it allows asymptotically secure key distribution and quasi-secure direct communication. Its absolute security has been proved. It is hoped that this kind of quantum deterministic communication will “Ping-pong” protocol is a novel secure deterministic quantum communication protocol. Based on an entangled pair of qubit, it allows asymptotically secure key distribution and quasi-secure direct communication. Its absolute security has been proved. It is hoped that this kind of quantum deterministic communication will be a main trend of the future quantum optic communication. However, there is no experimental implement of this protocol reported so far. The working scheme of the ping-pong protocol is analyzed and its flow chart is presented. Then the scheme of physical realization of the ping-pong protocol is analyzed. Combining entangled photon resource technique with single photon routing control and single photon detecting technique, an experimental realization in freespace of this protocol and its equipment figure are then proposed. Based on this work, further research of the ping-pong protocol and some practical applications can be taken..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 25, Issue 3, 425 (2005)
Rapid Communications
Infrared Scintillation Properties of Yb∶YAG Crystal
[in Chinese], [in Chinese], and [in Chinese]
Infrared (IR) scintillation properties of Yb∶YAG crystals with different Yb3+ doping level were measured by using pulsed electron beam. At room temperature the light yield of Yb∶YAG crystal is high and decay time is long. The dependence of light yield and decay time on Yb3+ doped concentration and temperature were demoInfrared (IR) scintillation properties of Yb∶YAG crystals with different Yb3+ doping level were measured by using pulsed electron beam. At room temperature the light yield of Yb∶YAG crystal is high and decay time is long. The dependence of light yield and decay time on Yb3+ doped concentration and temperature were demonstrated, and concentration quenthing was observed. The scintillation properties of Yb∶YAG were still affected by crystal quality. These measurement results suggest that some Yb3+-doped crystals should be possible for application in medical imaging..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 25, Issue 3, 429 (2005)
Experimental Study of Ultraviolet Laser-Induced Domain Reversion in LiNbO3 Crystals
[in Chinese], [in Chinese], [in Chinese], [in Chinese], and [in Chinese]
A method of realizing ultraviolet (UV) laser induced domain reverse in LiNbO3 crystals is investigated experimentally. With a certain external electric field, a sample of LiNbO3 crystal is illuminated by a UV laser beam of 365 nm wavelength. For the reason that the coercive field of the crystal is decreased by exposureA method of realizing ultraviolet (UV) laser induced domain reverse in LiNbO3 crystals is investigated experimentally. With a certain external electric field, a sample of LiNbO3 crystal is illuminated by a UV laser beam of 365 nm wavelength. For the reason that the coercive field of the crystal is decreased by exposure of UV light, it is only the illuminated region whose domain is reversed. The results prove that this method can be used to realize the fabrication of periodically poled LiNbO3 crystals, and it will become an effective solution to smaller periods..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 25, Issue 3, 431 (2005)
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