Contents
2001
Volume: 21 Issue 3
29 Article(s)
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Atmospheric Optics and Oceanic Optics
Analysis of an Adaptive Control Algorithm Used in an Adaptive Optical System
[in Chinese], [in Chinese], [in Chinese], and [in Chinese]
An adaptive control algorithm used in a practical adaptive optical (AO) system was analyzed. The adaptive control algorithm, differs like the traditional control algorithm, it considered the effect of atmospheric turbulence and the measurement noise together. The coefficients of the controller can change to adapt the wAn adaptive control algorithm used in a practical adaptive optical (AO) system was analyzed. The adaptive control algorithm, differs like the traditional control algorithm, it considered the effect of atmospheric turbulence and the measurement noise together. The coefficients of the controller can change to adapt the working environment of an AO system to make the compensation optimizing. The experimental results on the 61-element AO system were analyzed, and the methods to solve some practical problems with the algorithm were discussed..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 21, Issue 3, 283 (2001)
The Effects of Finite Outer Scale on the Measurement of Characterization of Atmospheric Turbulence Statistics
[in Chinese], and [in Chinese]
Phase structure function and aperture-averaged slope correlation function with finite outer scale are derived. The strong effects of finite outer scale on measurement of characterization of atmospheric turbulence statistics are shown, especially for large size telescope and subaperture. The phase structure function andPhase structure function and aperture-averaged slope correlation function with finite outer scale are derived. The strong effects of finite outer scale on measurement of characterization of atmospheric turbulence statistics are shown, especially for large size telescope and subaperture. The phase structure function and atmospheric coherent length based on Kolmogorov model is just the proximation of the formalism derived here. The analysis indicates that it can not be determined whether the deviation from the model of Kolmogorov turbulence is caused by real variance of spectrum or by the effect of finite outer scale..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 21, Issue 3, 290 (2001)
Diffraction and Gratings
Talbot Effect of a Grating under Ultrashort Pulsed-Laser Beam Illumination
[in Chinese], [in Chinese], [in Chinese], and [in Chinese]
An equation for calculating the Fresnel diffraction field of a grating under short-pulsed light illumination is derived. As an example, the equation is used to analyse the diffraction field of a rectangular grating with the opening ratio 1/4. The following results are found: Talbot self-imaging effect will appear when An equation for calculating the Fresnel diffraction field of a grating under short-pulsed light illumination is derived. As an example, the equation is used to analyse the diffraction field of a rectangular grating with the opening ratio 1/4. The following results are found: Talbot self-imaging effect will appear when the full width at half-maximum of the incident short-pulsed light (FWHM) Δτ is within picoseconds and it will be gradually diminished at Δτ becomes small. When Δτ is within a few decade femtoseconds, the maximal intensity of the diffraction field at the first Talbot distance decreases along with the decrease of Δτ..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 21, Issue 3, 320 (2001)
Fiber Optics and Optical Communications
Electrooptic Coefficient for the Silica Fiber after Thermal/Electric-Field Poling
[in Chinese], [in Chinese], and [in Chinese]
By using the multiple-carrier model and uniaxial symmetry and photoinduced mechanisms, the relationships of electrooptic coefficient γ with the distance d of D-fiber, poling time t and applied voltage V in the silica fiber after the thermal/electric-field poling (TEFP) are theoretically calculated. The results show thaBy using the multiple-carrier model and uniaxial symmetry and photoinduced mechanisms, the relationships of electrooptic coefficient γ with the distance d of D-fiber, poling time t and applied voltage V in the silica fiber after the thermal/electric-field poling (TEFP) are theoretically calculated. The results show that if d is short enough and poling time is suitable, the electrooptic coefficient can effectively be increased; the electrooptic coefficient is approximately proportional to the square-root of the applied dc voltage. The ratio of γ33/γ13 approaches to 3. The theoretical results are well consistent with experimental reports..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 21, Issue 3, 296 (2001)
High-Stability and Broad-Band Erbium-Doped Superfluorescent Fiber Source
[in Chinese], and [in Chinese]
Erbium-doped superfluorescent fiber sources (SFS) pumped near 980 nm in double-pass backward (DPB) configuration have been characterized through theoretical simulation. The results indicate that for a DPB SFS with a reflector of any reflectance, the pump-power independent mean-wavelength operation can always be achieveErbium-doped superfluorescent fiber sources (SFS) pumped near 980 nm in double-pass backward (DPB) configuration have been characterized through theoretical simulation. The results indicate that for a DPB SFS with a reflector of any reflectance, the pump-power independent mean-wavelength operation can always be achieved by properly adjusting the erbium-doped fiber (EDF) length. In the case of high stable mean-wavelength operation, the DPB SFS with the optimized reflector has a linewidth and pump efficiency obviously larger than SFSs in other configurations..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 21, Issue 3, 300 (2001)
Instrumentation, Measurement and Metrology
Analysis of Interferometer Systerm in a Large Aperture Static Imaging Spectrometer
[in Chinese], [in Chinese], and [in Chinese]
Characteristics of the large aperture static spectrometer (LASIS) are described from different aspects. Principles of its interferometer system is introduced. Design of the interferometer systerm based on lateral shearing interferometer is presented and analyzed. Two kinds of high étendue large view field lateral Characteristics of the large aperture static spectrometer (LASIS) are described from different aspects. Principles of its interferometer system is introduced. Design of the interferometer systerm based on lateral shearing interferometer is presented and analyzed. Two kinds of high étendue large view field lateral shearing interferometers are discussed. Primary merits of LASIS are summarized..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 21, Issue 3, 330 (2001)
Experimental Study for Optical Packet Switching Matrix
[in Chinese], [in Chinese], [in Chinese], and [in Chinese]
The principle of optical switching matrix is studied. The architecture, function,performance and related realization way in this system are introduced. The important parts are optical waveguide switch based on APE:LiNbO3 and corresponding system technology. The experimental result for 2.5 Gbit/s throughput in asynchronThe principle of optical switching matrix is studied. The architecture, function,performance and related realization way in this system are introduced. The important parts are optical waveguide switch based on APE:LiNbO3 and corresponding system technology. The experimental result for 2.5 Gbit/s throughput in asynchronous transfer mode (ATM) photonic cell is given..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 21, Issue 3, 335 (2001)
Study on Monocular Vision Method Used for Camera Positioning
[in Chinese], and [in Chinese]
The aim of this study is to determine the focusing position of camera relative to the measured point by monocular vision algorithm, and a new monocular vision algorithm is presented. The methods of position-from-defocus and position-from-focus in monocular vision method are combined to determine the focusing position. The aim of this study is to determine the focusing position of camera relative to the measured point by monocular vision algorithm, and a new monocular vision algorithm is presented. The methods of position-from-defocus and position-from-focus in monocular vision method are combined to determine the focusing position. A new kind of energy-spectrum entropy image focus criteria function and the calculation model of position-from-defocus method and position-from-focus method are given. The verification experimental results indicate the stability and reliability of the proposed algorithm..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 21, Issue 3, 339 (2001)
Measurement of Wavefront Power Spectral Density of Large Optical Components
[in Chinese], [in Chinese], [in Chinese], and [in Chinese]
The optical components employed in high power density solid-state laser for inertial confinement fusion (ICF) must be measured at full aperture to provide the higher resolution measurements necessary to detect mid-spatial-frequency errors in the wavefront. The use of Fourier analysis techniques to measure the wavefrontThe optical components employed in high power density solid-state laser for inertial confinement fusion (ICF) must be measured at full aperture to provide the higher resolution measurements necessary to detect mid-spatial-frequency errors in the wavefront. The use of Fourier analysis techniques to measure the wavefront power spectral density (PSD) in mid-frequency domain is discussed. A large phase-shifting Fizeau interferometer is used for the measurement. The phase wavefront detected by the interferometer is digitally processed to create one dimension wavefront PSD. The PSD of several optical components are shown..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 21, Issue 3, 344 (2001)
Study on Instantaneous Temperature Measurement in a Flame by LIPF
[in Chinese], [in Chinese], [in Chinese], [in Chinese], [in Chinese], and [in Chinese]
The principles and the experimental results for temperature measurements by laser-induced predissociative fluorescence (LIPF) are presented. With a tunable KrF excimer laser, the fluorescence of OH radical was obtained in a methane-air flame at the pressure of atmosphere and the structures of the spectrum were analyzedThe principles and the experimental results for temperature measurements by laser-induced predissociative fluorescence (LIPF) are presented. With a tunable KrF excimer laser, the fluorescence of OH radical was obtained in a methane-air flame at the pressure of atmosphere and the structures of the spectrum were analyzed. The temperatures in the flame were also measured by LIPF narrow-band and broad-band methods. By selecting proper excited lines, subtracting background noises and choosing moderate laser energy, both the precision is less than 3%..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 21, Issue 3, 348 (2001)
A Differential Optic Phase Tracing Method in Fiber Optic Gyro
[in Chinese], and [in Chinese]
The fundamental step to acquire the rotation rate of fiber optic gyro (FOG) is to detect the differential optic phase. The characters of FOG’s output signal which are with large noise, nonlinear, periodic and their consequences to the detection of the effective signal are analyzed briefly. Here a tracing of differentiaThe fundamental step to acquire the rotation rate of fiber optic gyro (FOG) is to detect the differential optic phase. The characters of FOG’s output signal which are with large noise, nonlinear, periodic and their consequences to the detection of the effective signal are analyzed briefly. Here a tracing of differential optic phase is presented and sin modulation is adopted in the method, triangular operator is applied and finally the rotation signal is gotten after multipling on FOG output and the tracing signal, and adding filters to where they are needed. With this method the dynamic range and the linear of scale factor of FOG are improved. It also has the advantages of simple, low cost and easy to accomplished. The phase tracing simulation and the test circuit are made and the results are given..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 21, Issue 3, 352 (2001)
Lasers and Laser Optics
A Scheme of Uranium Isotope Enrichment via Magnetic Deflection of an Atomic Beam Polarized by Laser Pumping
[in Chinese], [in Chinese], [in Chinese], and [in Chinese]
A scheme of magnetic deflection of an atomic beam polarized by laser pumping applied to isotope enrichment of uranium is presented. The characteristics of magnetic deflection for all sub-levels in the ground state of uranium atoms were evaluated. An experimental method of selectively polarized uranium atoms by optical A scheme of magnetic deflection of an atomic beam polarized by laser pumping applied to isotope enrichment of uranium is presented. The characteristics of magnetic deflection for all sub-levels in the ground state of uranium atoms were evaluated. An experimental method of selectively polarized uranium atoms by optical pumping was proposed. The available enrichment result in this scheme was discussed..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 21, Issue 3, 262 (2001)
Study for Laser-Induced Periodic Surface Structure of PET Fiber by Heat Model
[in Chinese], [in Chinese], [in Chinese], [in Chinese], [in Chinese], and [in Chinese]
This work characterizes the laser-induced periodic surface structure of PET fiber by 308 nm excimer laser. The heat model on enthalpy was set up for interaction between the laser and PET. The melt phenomenon was important for surface structure formation. The surface temperature, melt depth and melt depth dependences ofThis work characterizes the laser-induced periodic surface structure of PET fiber by 308 nm excimer laser. The heat model on enthalpy was set up for interaction between the laser and PET. The melt phenomenon was important for surface structure formation. The surface temperature, melt depth and melt depth dependences of time and liquid/solid interface move velocity were numerically calculated..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 21, Issue 3, 267 (2001)
Frequency-Stabilized High Power Nd:YVO4 Ring Single-Frequency Laser End-Pumped by Diode Laser
[in Chinese], [in Chinese], [in Chinese], and [in Chinese]
A CW frequency-stability ring Nd:YVO-4 laser end-pumped by a laser diode through fiber-coupling is designed and experimentally demonstrated. The output laser frequency is locked at the central frequency of Fabry-Pero confocal reference cavity, the frequency stability was better than 400 kHz. Up to 2 W output power withA CW frequency-stability ring Nd:YVO-4 laser end-pumped by a laser diode through fiber-coupling is designed and experimentally demonstrated. The output laser frequency is locked at the central frequency of Fabry-Pero confocal reference cavity, the frequency stability was better than 400 kHz. Up to 2 W output power with the frequency-stability better than 620 kHz is achieved at 6 W input power. The conversion efficiency from light to light is 33.3% and the conversion efficiency from electric power to light is 10%..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 21, Issue 3, 271 (2001)
Study of an Efficient Nd:YVO4 Red Light Laser Pumped by Laser Diode
[in Chinese], [in Chinese], [in Chinese], [in Chinese], [in Chinese], [in Chinese], and [in Chinese]
A high power LD end-pumped Nd:YVO4 intracavity frequency-doubled 671 nm laser is demonstrated. A thin lens model is introduced to design a thermally-insensitive cavity. The output power of 890 mW at 671 nm is achieved with a type-Ⅱ noncritical phase-matched (NCPM) LBO crystal.A high power LD end-pumped Nd:YVO4 intracavity frequency-doubled 671 nm laser is demonstrated. A thin lens model is introduced to design a thermally-insensitive cavity. The output power of 890 mW at 671 nm is achieved with a type-Ⅱ noncritical phase-matched (NCPM) LBO crystal..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 21, Issue 3, 274 (2001)
A Global Optimization and Design of a Copper Vapor Laser with 100 W Order for Obtaining Maximum Output
[in Chinese], [in Chinese], [in Chinese], and [in Chinese]
Both the laser head and the discharge circuit of a copper vapor laser (CVL) are optimizingly designed and determined for obtaining a maximum output by applying a global optimizing genetic algorithm. One way of increasing the laser output is to increase the input power (in which the peak voltage is primary) and to raiseBoth the laser head and the discharge circuit of a copper vapor laser (CVL) are optimizingly designed and determined for obtaining a maximum output by applying a global optimizing genetic algorithm. One way of increasing the laser output is to increase the input power (in which the peak voltage is primary) and to raise properly the wall-temperature while maintaining a smaller storage capacitor compared the experimental value..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 21, Issue 3, 278 (2001)
Materials
Characteristics of Various Diffuser Materials at UV-VUV Spectral Range
[in Chinese], and [in Chinese]
Characteristics of a ground aluminium diffuse plate at ultraviolate-vacuum ultraviolate(UV-VUV)and that of a BaSO4 and a polytetrafluoroethylene (PTFE) diffuse plate at UV are described. The ρ(0,d) of the BaSO4 and the ground aluminium diffuse plate in 250 nm～400 nm is measured by comparing with the PTFE diffuse plate Characteristics of a ground aluminium diffuse plate at ultraviolate-vacuum ultraviolate(UV-VUV)and that of a BaSO4 and a polytetrafluoroethylene (PTFE) diffuse plate at UV are described. The ρ(0,d) of the BaSO4 and the ground aluminium diffuse plate in 250 nm～400 nm is measured by comparing with the PTFE diffuse plate whose ρ(0,d) is known. Also,the aging of the ρ(0,d) of the BaSO4 diffuse plate is presented. The fBRDF(0,θd) of the three diffuse materials is calculated..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 21, Issue 3, 371 (2001)
Nonlinear Optics
Violet Laser Output Based on Frequency Doubling of Diode Laser Using ZCTC Crystal
[in Chinese], [in Chinese], [in Chinese], [in Chinese], [in Chinese], [in Chinese], [in Chinese], and [in Chinese]
Optical properties of a new type metal coordination complex nonlinear optical crystal zinc cadmium thiocyanate (ZCTC) are reported. Refractive index is measured and phase-matching angles are calculated. Direct frequency doubling of diode laser radiation has been achieved using ZCTC crystal at room temperature. With 473Optical properties of a new type metal coordination complex nonlinear optical crystal zinc cadmium thiocyanate (ZCTC) are reported. Refractive index is measured and phase-matching angles are calculated. Direct frequency doubling of diode laser radiation has been achieved using ZCTC crystal at room temperature. With 473 mW input power of 808 nm GaAlAs diode laser, 390 μW output at 404 nm violet light were produced. Experimental results show that ZCTC crystal is a promising excellent violet nonlinear optical material for frequency doubling of diode laser..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 21, Issue 3, 305 (2001)
Optical Devices
Mechanism of Voigt Anomalous Dispersion Optical Filter
[in Chinese], [in Chinese], [in Chinese], and [in Chinese]
The mechanism and performances of Voigt anomalous dispersion atomic optical filter (VADOF) are studied. The experimental results agree well with the theoretical calculation. When the magnetic field is 0.02 T and the cell temperature is 110 ℃, this kind of filter exhibited a FWHM of 0.8 GHz which is 0.5 GHz smaller thanThe mechanism and performances of Voigt anomalous dispersion atomic optical filter (VADOF) are studied. The experimental results agree well with the theoretical calculation. When the magnetic field is 0.02 T and the cell temperature is 110 ℃, this kind of filter exhibited a FWHM of 0.8 GHz which is 0.5 GHz smaller than that of Faraday anomalous dispersion optical filter (FADOF), and the VADOF is easy to be integrated than FADOF. VADOF has a potential application in the field of optical communication inter-satellite..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 21, Issue 3, 357 (2001)
Study of Reentrant Fiber Optical Rotation Sensor
[in Chinese], [in Chinese], and [in Chinese]
A novel reentrant fiber optical rotation sensor (RE-FORS) is designed and demonstrated. The analytic equations of the optical transmitance, the phase sensitivity and the resolution of RE-FORS were deduced. The contribution to the sensitivity and the resolution of RE-FORS the coupling ratio of the resonator coupler was A novel reentrant fiber optical rotation sensor (RE-FORS) is designed and demonstrated. The analytic equations of the optical transmitance, the phase sensitivity and the resolution of RE-FORS were deduced. The contribution to the sensitivity and the resolution of RE-FORS the coupling ratio of the resonator coupler was estimated. According to the theoretical considerations of the sensitivity and the resolution, the setup for investigating RE-FORS with 200-meter-length of ring resonator (RR) was developed. As shown by the test results, the RE-FORS setup has the constant bias of 0.2(°/h) and the variance of random drift rate better than 0.1(°/h) (the integration time of 10 s and the sampling length of 10 min were used)..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 21, Issue 3, 363 (2001)
Modeling of Maltimode Interference Mach-Zehnder Interferometer Optical Switches
[in Chinese], [in Chinese], [in Chinese], [in Chinese], [in Chinese], [in Chinese], and [in Chinese]
N×N Multimode interference(MMI) couplers are investigated. The mode field transmitting matrix based on the phase relations in MMI couplers is introduced to analyze the MMI couplers. Field transmitting equations of MMI couplers, phase shifter and Mach-Zehnder interferometer (MZI) optical switches are derived. The dN×N Multimode interference(MMI) couplers are investigated. The mode field transmitting matrix based on the phase relations in MMI couplers is introduced to analyze the MMI couplers. Field transmitting equations of MMI couplers, phase shifter and Mach-Zehnder interferometer (MZI) optical switches are derived. The driving conditions of MZI switches for different switching situations are obtained by solving the field transmitting equations. The design of 4×4 switch is completed for a promising silicon-on-insulator waveguide structure..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 21, Issue 3, 367 (2001)
Physical Optics
Focus Characteristics of Laser Beam for Long Distance Propagation in Atmosphere
[in Chinese], [in Chinese], [in Chinese], [in Chinese], [in Chinese], and [in Chinese]
The influence of atmospheric turbulence and thermal blooming on focus characteristics of laser beam is studied for several typical lasers with different wavelength. The excursion of the laser beam axis for long distance propagation in atmosphere is obtained for several laser beam axes. The calculations coincide with thThe influence of atmospheric turbulence and thermal blooming on focus characteristics of laser beam is studied for several typical lasers with different wavelength. The excursion of the laser beam axis for long distance propagation in atmosphere is obtained for several laser beam axes. The calculations coincide with the experimental result..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 21, Issue 3, 324 (2001)
Quantum Optics
Effects of Additive Noise on First-Order-Like Phase Transition in a Laser System
[in Chinese], and [in Chinese]
The steady state intensity distribution function is derived from a single mode gain-noise laser model. The extrema of the steady state distribution function is investigated as the additive noise, multiplicative noise and injected signal are changing. It is shown that the multiplicative noise plays a key rule in the firThe steady state intensity distribution function is derived from a single mode gain-noise laser model. The extrema of the steady state distribution function is investigated as the additive noise, multiplicative noise and injected signal are changing. It is shown that the multiplicative noise plays a key rule in the first-order-like phase transition in a laser system. The injected signal can reduce the phase transition. The additive noise causes the number and locations of the extrema in the steady state distribution function jumping back and forth..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 21, Issue 3, 257 (2001)
Rapid Communications
A Technique of Deformed Speciment Grating Replication for in Situ Measurement of Moire Interferometry
[in Chinese], [in Chinese], and [in Chinese]
An in situ measurement technique-deformed specimen replication has been given. The recorded information on the deformed specimen grating can be extracted by using a typical four-beam moire interferometer. Typical fringe pattern of U-field and V-field displacement contours obtained from the test. The theoretical analysiAn in situ measurement technique-deformed specimen replication has been given. The recorded information on the deformed specimen grating can be extracted by using a typical four-beam moire interferometer. Typical fringe pattern of U-field and V-field displacement contours obtained from the test. The theoretical analysis and experimental result have proved that the technique with the advantages of real time moire interferometry is suitable for a wide range of applications..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 21, Issue 3, 376 (2001)
Measurement of Converse Piezoelectric Expend and Contract of PZT with the Axial Response Curve of Fiber-Optical Confocal Scanning Imaging Microscope
[in Chinese], [in Chinese], [in Chinese], and [in Chinese]
By utilizing the axial response curve of fiber optical confocal scanning microscope, a new technique for measuring the micro position has been developed. Using this technique, the converse piezoelectric expend and contract of PZT with resolution as high as 5 nm was measured.By utilizing the axial response curve of fiber optical confocal scanning microscope, a new technique for measuring the micro position has been developed. Using this technique, the converse piezoelectric expend and contract of PZT with resolution as high as 5 nm was measured..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 21, Issue 3, 380 (2001)
Progress of Optical Homogeneity and Weak-Absorption of Large-Sized Sapphire Crystal Used in LIGO Project
[in Chinese], [in Chinese], [in Chinese], [in Chinese], [in Chinese], and [in Chinese]
The latest progress in the study of optical homogeneity and weak-absorption of large-sized sapphire crystal (φ113 mm×70 mm) is reported. The polishing precision of the whole crystal surface reaches 1.666λ, and the transfer wavefront distortion is 0.584λ. The transmission is higher than 80% at UV waveband and than The latest progress in the study of optical homogeneity and weak-absorption of large-sized sapphire crystal (φ113 mm×70 mm) is reported. The polishing precision of the whole crystal surface reaches 1.666λ, and the transfer wavefront distortion is 0.584λ. The transmission is higher than 80% at UV waveband and than 86% at VIS-NIR waveband. The weak-absorption coeffcient is 35×10-6 /cm～65×10-6 /cm..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 21, Issue 3, 383 (2001)
Spectroscopy
Theoretical and Experimental Investigation of Low-Frequency Wavelength Modulation Spectroscpy
[in Chinese], [in Chinese], [in Chinese], [in Chinese], and [in Chinese]
A series of experiments are carried out by modulating piezo voltage of an external-cavity continuously tunalbe diode laser. Cesium atom D2 line (6S1/2→6P3/2) absorption spectrum is measured by harmonic detection with a lock-in amplifier. The results about various harmonic signals in experiment are agreement with that iA series of experiments are carried out by modulating piezo voltage of an external-cavity continuously tunalbe diode laser. Cesium atom D2 line (6S1/2→6P3/2) absorption spectrum is measured by harmonic detection with a lock-in amplifier. The results about various harmonic signals in experiment are agreement with that in theory. The high-order harmonic detection may result in a significant improvement in signal-to-noise-ratio (SNR)..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 21, Issue 3, 317 (2001)
Thin Films
Study on the Optical Properties of PbTiO3 Film Deposited on α-Al2O3 with RF-Sputtering System
[in Chinese], [in Chinese], [in Chinese], and [in Chinese]
PbTiO3 thin film with pervoskite-type microstructure was synthesized directly on the α-Al2O3 substrate using a RF-magnetron sputtering system with a composite target. An effective method was developed to get the optical properties from the transmittance spectrum of the sample, and the dependences of refractive index anPbTiO3 thin film with pervoskite-type microstructure was synthesized directly on the α-Al2O3 substrate using a RF-magnetron sputtering system with a composite target. An effective method was developed to get the optical properties from the transmittance spectrum of the sample, and the dependences of refractive index and extinctive coefficient on wavelength were calculated with this method. The band-gap energy of the film was found to be 3.65 eV from the linear fitting of the absorption coefficient to the Tauc plot of (αhν)2 vs hν..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 21, Issue 3, 309 (2001)
Effects of Sputtering Ar Pressure on the Optical Constants of Ge2Sb2Te5 Thin Films
[in Chinese], [in Chinese], [in Chinese], [in Chinese], [in Chinese], and [in Chinese]
The effects of sputtering Ar pressure on optical constants (n,k) of Ge2Sb2Te5 thin films in the wavelength range from 300 nm to 900 nm were studied. The results show that the refractive index (n) first increases and then decreases with increasing Ar pressure, whereas the extinction coefficient (k) changes with Ar pressThe effects of sputtering Ar pressure on optical constants (n,k) of Ge2Sb2Te5 thin films in the wavelength range from 300 nm to 900 nm were studied. The results show that the refractive index (n) first increases and then decreases with increasing Ar pressure, whereas the extinction coefficient (k) changes with Ar pressure in a contrary way to that of n. The extent of the influence of Ar pressure on n and k also changes with wavelength. It is greater in the long wavelength region than in the short wavelength region. The mechanism on which the optical constants of the Ge2Sb2Te5 thin films are affected by the Ar pressure is discussed based on the variation of the atomic density and microstructure of the films..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 21, Issue 3, 313 (2001)
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