Contents
2002
Volume: 22 Issue 7
29 Article(s)
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Atmospheric Optics and Oceanic Optics
Image Deconvolution from Hartmann-Shack Wavefront Sensing:Indoors Experimental Results
[in Chinese], [in Chinese], and [in Chinese]
Based on the brief introduction of Hartmann Shack wavefront sensor and image deconvolution from wavefront sensing, the experimental results of image restoration of the objects with aberration by deconvolving from wavefront sensing are presented for point sources and extended sources respectively. The results show that Based on the brief introduction of Hartmann Shack wavefront sensor and image deconvolution from wavefront sensing, the experimental results of image restoration of the objects with aberration by deconvolving from wavefront sensing are presented for point sources and extended sources respectively. The results show that the post processing technique of deconvolution from wavefront sensing can efficiently be used to restore the image with aberration..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 22, Issue 7, 789 (2002)
Fiber Optics and Optical Communications
4×10 Gb/s 412 km DWDM Dispersion Compensation Using Multiwavelength Chirped Fiber Bragg Grating
[in Chinese], [in Chinese], [in Chinese], [in Chinese], [in Chinese], [in Chinese], [in Chinese], [in Chinese], and [in Chinese]
A new multiwavelength chirped fiber Bragg grating (MCFBG), with ITU T standard wavelength and space of neighbored wavelength was fabricated. The one MCFBG can compensate multichannels′ dispersion of 100 km fiber span at the same time. Experiment of 4×10 Gb/s 412 km WDM dispersion compensation without bit error ratA new multiwavelength chirped fiber Bragg grating (MCFBG), with ITU T standard wavelength and space of neighbored wavelength was fabricated. The one MCFBG can compensate multichannels′ dispersion of 100 km fiber span at the same time. Experiment of 4×10 Gb/s 412 km WDM dispersion compensation without bit error rate have been demonstrated. The compensative result with MCFBG is better than that with dispersion compensation fiber module..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 22, Issue 7, 839 (2002)
The Hybrid Direct Sequence/Frequency Hopping Optical CDMA System with FBGs based Encoder/Decoder
[in Chinese], [in Chinese], and [in Chinese]
A hybrid direct sequence/frequency hopping (DS/FH) scheme is proposed for optical code division multiple access (OCDMA) system. The optical encoder/decoder with prime hop sequence is based on fiber Bragg gratings (FBGs), and double optical hard limiters are placed on both sides of decoder respectively. With such a desiA hybrid direct sequence/frequency hopping (DS/FH) scheme is proposed for optical code division multiple access (OCDMA) system. The optical encoder/decoder with prime hop sequence is based on fiber Bragg gratings (FBGs), and double optical hard limiters are placed on both sides of decoder respectively. With such a design, the DS/FH OCDMA system has large number of simultaneous user, high power efficiency and low bit error rate (BER)..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 22, Issue 7, 842 (2002)
Fourier Optics and Signal Processing
Noise Bias Compensation in the Iterative Shift-and-Add Method for Astronomical Image Reconstruction
[in Chinese], [in Chinese], [in Chinese], and [in Chinese]
Because there are many kinds of noise, the noise bias terms are introduced in the iterative shift and add method for astronomical image reconstruction when working in real data. To overcome the influence of the noise bias terms, the system error involved by the differences of the atmospheric seeing during the observatiBecause there are many kinds of noise, the noise bias terms are introduced in the iterative shift and add method for astronomical image reconstruction when working in real data. To overcome the influence of the noise bias terms, the system error involved by the differences of the atmospheric seeing during the observation of the speckle data of the object and referenc star; and the bias come from serious additive noise of the detector were discussed. The methods for the compensation of these noise bias terms were given..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 22, Issue 7, 829 (2002)
An Improved Biblock Zero Tree Coding for Hyperspectral Data Compression
[in Chinese], [in Chinese], [in Chinese], and [in Chinese]
An improved biblock zero tree compression coding (IBBZTC) method with predictive binary scalar quantization and a compression ratio formula is given. The IBBZTC way is applied for hyperspectral data compression. This method is characterized by ZTC′s high compression ratio, real time implementing, and advantages of highAn improved biblock zero tree compression coding (IBBZTC) method with predictive binary scalar quantization and a compression ratio formula is given. The IBBZTC way is applied for hyperspectral data compression. This method is characterized by ZTC′s high compression ratio, real time implementing, and advantages of higher coding/decoding speed and real time transmission. The experimental results show that the total compression performance of IBBZTC outperforms the KL transformation joint photographic experts group (KLT JPEG), wavelet transform vector quantization (WT VQ), wavelent transform zero tree vector quantization (WT ZTVQ) and biblock zero tree coding (BBZTC) compression methods without transmitting residue error. Compression rate is 190 times, and peak SNR is above 30 dB..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 22, Issue 7, 834 (2002)
Instrumentation, Measurement and Metrology
Study on the Method of Matching Detection of Fiber Grating Vibration Sensor
[in Chinese], [in Chinese], [in Chinese], [in Chinese], and [in Chinese]
The methods of sensor and demodulation with matched fiber Bragg gratings (FBG) used as direct light intensity elements in vibration sensor are introduced. The expressions of reflection and transmission spectra of FBG are deduced, which provides a qualitative explanation of sensor mechanism. Then mathematical models areThe methods of sensor and demodulation with matched fiber Bragg gratings (FBG) used as direct light intensity elements in vibration sensor are introduced. The expressions of reflection and transmission spectra of FBG are deduced, which provides a qualitative explanation of sensor mechanism. Then mathematical models are established in order to make simulation. The method can perform single point demodulation with matched FBG and can turn the sensor signals into intensity variation of the output of FBG. The experimental results are in excellent agreement with the theory, which proves the feasibility of this method..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 22, Issue 7, 847 (2002)
Development of Elementary Arrangement for Exterme Ultraviolet Projection Lithography
[in Chinese], [in Chinese], [in Chinese], and [in Chinese]
The prototype for extreme ultraviolet projection lithography at 13 nm wavelength includes a laser plasma source, an ellipsoidal condenser, a transmission mask, the Schwarzschild objective, a resist coated wafer and the associated vacuum apparatus. The optical design is optimized to achieve a resolution better than 0.1 The prototype for extreme ultraviolet projection lithography at 13 nm wavelength includes a laser plasma source, an ellipsoidal condenser, a transmission mask, the Schwarzschild objective, a resist coated wafer and the associated vacuum apparatus. The optical design is optimized to achieve a resolution better than 0.1 μm over a 0.1 mm diameter image field of view..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 22, Issue 7, 852 (2002)
Chopping Adaptive Phase-Shifting Interferometry
[in Chinese], and [in Chinese]
An adaptive phase shifting interferometry, insensitive to the disturbance of constant term of phase perturbations induced by environmental vibration and air turbulence is discussed. where the polarization characteristic and high frequency intensity modulation of laser beam and phase lock in as well as the closed loop cAn adaptive phase shifting interferometry, insensitive to the disturbance of constant term of phase perturbations induced by environmental vibration and air turbulence is discussed. where the polarization characteristic and high frequency intensity modulation of laser beam and phase lock in as well as the closed loop control techniques are used, and a chopping adaptive phase shifting interfernece system was set up. The wobble of interference fringes can be compensated, and sequentially be locked at arbitrarily chosen phase for phase shifting testing. Comparing with other similar techniques, here the depth of signal modulation is not limited by the magnitude of optical path difference and the fringe contrast is not reduced by the modulation, hence a high signal to noise ratio can be obtained. The principle and structure of the chopping adaptive phase shifting interferometer are described. The experimental results and conclusions are presented..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 22, Issue 7, 858 (2002)
Surface Measurement of LCD Substrate by Noncontact Light Probe Flatness Tester
[in Chinese], [in Chinese], and [in Chinese]
A kind of flatness tester with noncontact light probe is introduced. It has the accuracy of nanometer, with a resolution of 1 nm, and measuring range of 10 μm. This kind of tester shows a great practical prospect in the applications of electronic glass, semiconductor, integrated circuit, thin films and technology of naA kind of flatness tester with noncontact light probe is introduced. It has the accuracy of nanometer, with a resolution of 1 nm, and measuring range of 10 μm. This kind of tester shows a great practical prospect in the applications of electronic glass, semiconductor, integrated circuit, thin films and technology of nanometer. Some of the testing results in the study of liquid crystal device (LCD) substrate surface shapes by the tester are presented and the results indicate that this kind of tester can be used in LCD study and play an important role in it..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 22, Issue 7, 863 (2002)
Lasers and Laser Optics
Wavelength Tunable Mode-Locked Fiber Ring Laser Utilized by the Dispersion of CFBG
[in Chinese], [in Chinese], [in Chinese], [in Chinese], [in Chinese], [in Chinese], [in Chinese], [in Chinese], and [in Chinese]
A wavelength tunable mode-locked fiber ring laser is described, in which a chirped fiber Bragg grating (CFBG) is included to give a large dispersion in the cavity. By tuning the modulating frequency, the wavelength of pulse laser is tuned. The tuning range is about 2 nm, limited by the spectral band of CFBG. The pulsesA wavelength tunable mode-locked fiber ring laser is described, in which a chirped fiber Bragg grating (CFBG) is included to give a large dispersion in the cavity. By tuning the modulating frequency, the wavelength of pulse laser is tuned. The tuning range is about 2 nm, limited by the spectral band of CFBG. The pulses with positive chirp are obtained. The frequency of pulse is 2.5 GHz and pulse width is about 60 ps..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 22, Issue 7, 822 (2002)
Analog Calculation and Evaluation of LDA Direct Side-Pumping
[in Chinese], [in Chinese], and [in Chinese]
A calculating model of laser diode side pumping method is proposed, and the effects of the parameters (absorption coefficient and distance between the laser diode and the medium) on the homogeneity are discussed. It is concluded that the high pumping efficiency can be obtained in direct side pumping method.A calculating model of laser diode side pumping method is proposed, and the effects of the parameters (absorption coefficient and distance between the laser diode and the medium) on the homogeneity are discussed. It is concluded that the high pumping efficiency can be obtained in direct side pumping method..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 22, Issue 7, 825 (2002)
Materials
Absorption Spectra of Colored Transparent Glass Ceramic
[in Chinese], [in Chinese], [in Chinese], [in Chinese], [in Chinese], and [in Chinese]
The transparent colored glass ceramics were obtained and based on the controlled nucleation and crystallization of Li 2O Al 2O 3 SiO 2 system glasses containing little TiO 2, ZrO 2 and P 2O 5 as nucleating agent and rare earth of transition metal ions as coloration agent. The temperature of nucleation and crystallizatiThe transparent colored glass ceramics were obtained and based on the controlled nucleation and crystallization of Li 2O Al 2O 3 SiO 2 system glasses containing little TiO 2, ZrO 2 and P 2O 5 as nucleating agent and rare earth of transition metal ions as coloration agent. The temperature of nucleation and crystallization was determined with DTA analysis. The transmission of the obtained glass ceramics were measured and investigated in the range of ultraviolet to near infrared wavelength. The results show that the transmission of glass ceramic is reduced due to the scatter of micro crystallites for the light, while the instinct absorption peaks of rare earth in the host glass are almost the same as that after nucleation crystallization of the glass. The effects of glass and glass ceramics on the absorption spectra of rare earth and transition metal ions were discussed..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 22, Issue 7, 878 (2002)
Electro-Optic Properties and Relaxation of Nano-Crystal and Polymer Composite Thin Film PbTiO3-PEK-c
[in Chinese], [in Chinese], [in Chinese], [in Chinese], [in Chinese], [in Chinese], [in Chinese], [in Chinese], and [in Chinese]
Polyetherketone (PEKc) guest host polymer thin films doped with nano crystal (PbTiO3) were prepared. The linear electro optic coefficient (Pockels coefficient) of the composite thin film was measured by the simple transmission technique. And the relaxation of electro optic coefficient of the film was investigated.Polyetherketone (PEKc) guest host polymer thin films doped with nano crystal (PbTiO3) were prepared. The linear electro optic coefficient (Pockels coefficient) of the composite thin film was measured by the simple transmission technique. And the relaxation of electro optic coefficient of the film was investigated..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 22, Issue 7, 882 (2002)
Effect of Heat Treatment on Properties of Li2O-Al2O3A-SiO2 System Glass
[in Chinese], [in Chinese], [in Chinese], [in Chinese], and [in Chinese]
The physical properties of the Li 2O Al 2O 3 SiO 2 system based zero expansion glass ceramic of V02 have been measured during a linearly temperature raise. There is a significant change in a narrow temperature range for all physical properties caused by the phase transformation. The refractive index increases from 1.52The physical properties of the Li 2O Al 2O 3 SiO 2 system based zero expansion glass ceramic of V02 have been measured during a linearly temperature raise. There is a significant change in a narrow temperature range for all physical properties caused by the phase transformation. The refractive index increases from 1.5258 to 1.5433. The density increases from 2.563 to 2.576 g/cm 3. The expansion coefficient decrease from 41.5×10 -7 /℃ to near zero. The Knoop hardness increases from 57.8 MPa to 76.4 MPa. The total linear shrinkage is 1.12%. The optical transmission at short wavelength region decreases first and then increases with heat treatment temperature raise. Some useful points were suggested for controlled crystallization of large glass mirror blank..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 22, Issue 7, 886 (2002)
Nonlinear Optics
Second Harmonic Emission from fs Laser and Underdense Plasma Interaction
Tang Yuhui, Han Shensheng, Zhang Changxue, Wu Yanqing, Cheng Jing, Zhong Fangchuan, Zhu Yuzhe, and Xu Zhizhan
The experimental results of the second harmonic emission (SHE) in an ultrashort (45fs, 6×10 17 W/cm 2) laser pulse interaction with underdense plasmas formed from an optically ionized helium gas are presented. The spectra of SHE are measured under different intensities of fs laser pulses and the gas densities. TheThe experimental results of the second harmonic emission (SHE) in an ultrashort (45fs, 6×10 17 W/cm 2) laser pulse interaction with underdense plasmas formed from an optically ionized helium gas are presented. The spectra of SHE are measured under different intensities of fs laser pulses and the gas densities. The relationship between the conversion efficiency of SHE and the laser energy is studied. The theoretical explanation is given to the origin of SHE in underdense plasma. In consideration of the radial electron density gradient in plasmas produced by the intense ultrashort pulses propagation in the gas, a good agreement is obtained between experimental results and theoretical curve based on the nonlinear process..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 22, Issue 7, 780 (2002)
Influence of Encounter Time on Brillouin Amplification
[in Chinese], [in Chinese], and [in Chinese]
Brillouin amplifier was numerically simulated by the theory model of transient stimulated Brillouin scattering including depleted pump. Energy extract efficiency. Stokes seed amplification factor and Stokes output pulse width versus encounter time in the Brillouin amplifier were given. Three different encounter times wBrillouin amplifier was numerically simulated by the theory model of transient stimulated Brillouin scattering including depleted pump. Energy extract efficiency. Stokes seed amplification factor and Stokes output pulse width versus encounter time in the Brillouin amplifier were given. Three different encounter times were experimentally studied. The theoretical calculation was coincident with experimental results well..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 22, Issue 7, 784 (2002)
Optical Design and Fabrication
A Parametric Model of Bidirectional Reflectance Distribution Function
[in Chinese], [in Chinese], and [in Chinese]
The study of the parametric theory of bidirectional reflectance distribution function (BRDF) for the coating material is presented. The 3 parameter formula of BRDF is obtained. By optimizing the parameters, the parametric models of BRDF for several typical coating samples are demonstrated. A comparison of this parametrThe study of the parametric theory of bidirectional reflectance distribution function (BRDF) for the coating material is presented. The 3 parameter formula of BRDF is obtained. By optimizing the parameters, the parametric models of BRDF for several typical coating samples are demonstrated. A comparison of this parametric model with the experimental results shows that both results are in agreement well. This method for calculating BRDF of rough surface is simple in form and practicable in the engineering applications..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 22, Issue 7, 769 (2002)
Analysis of Rigorous Modal Theory for Arbitrary Dielectric Gratings Made with Anisotropic Materials
[in Chinese], [in Chinese], [in Chinese], and [in Chinese]
The diffraction properties of electromagnetic anisotropic gratings with arbitrary profile, illuminated at an arbitrary incidence angle are studied, by generalizing Fourier series expansion method of inverse rule and recursive algorithm of reflection transmission coefficient matrix. The physical concepts are clear in thThe diffraction properties of electromagnetic anisotropic gratings with arbitrary profile, illuminated at an arbitrary incidence angle are studied, by generalizing Fourier series expansion method of inverse rule and recursive algorithm of reflection transmission coefficient matrix. The physical concepts are clear in this method, and its numerical calculation, compared with those of other methods, are stable, convergent and fast..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 22, Issue 7, 774 (2002)
Optical Devices
Simultaneous Measurement of Strain and Temperature Using a Single Dual-Period Fiber Grating
[in Chinese], [in Chinese], [in Chinese], [in Chinese], and [in Chinese]
A novel dual period fiber grating sensor is demonstrated, which can measure strain and temperature simultaneously. The dual period fiber grating consists of a long period fiber grating (LPG) and a fiber Bragg grating (FBG) which is written in the same section of an uncovered hydrogen loaded fiber orderly. The Bragg wavA novel dual period fiber grating sensor is demonstrated, which can measure strain and temperature simultaneously. The dual period fiber grating consists of a long period fiber grating (LPG) and a fiber Bragg grating (FBG) which is written in the same section of an uncovered hydrogen loaded fiber orderly. The Bragg wavelength of LPG and that of FBG have different sensitivity to strain and temperature, then strain and temperature can be determined simultaneously by measuring the two transmitted Bragg wavelengths of the dual period fiber grating. The accuracy of the sensory in measuring strain and temperature is estimated to be ±16 με in a range from 0 to 1700 με and ±0.8 ℃ from 20 ℃ to 120 ℃ respectively..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 22, Issue 7, 867 (2002)
A Weak Optical Switch in GaAs-AlGaAs Asymmetric Coupled Quantum Wells
[in Chinese], [in Chinese], [in Chinese], and [in Chinese]
A scheme of a weak optical switch in GaAs-AlGaAs asymmetric coupled quantum wells is proposed. The effect of dephasing rate γ 21 on the switch is analysized. The optical switch is induced by Fano interference in coherent effects between inter subbands in superlattices. This weak semiconductor switch is more practical tA scheme of a weak optical switch in GaAs-AlGaAs asymmetric coupled quantum wells is proposed. The effect of dephasing rate γ 21 on the switch is analysized. The optical switch is induced by Fano interference in coherent effects between inter subbands in superlattices. This weak semiconductor switch is more practical than that of atomic media due to its flexibility for choosing materials and structure dimensions of the utilized heterostructures. This is also a method of controlling one beam by another in semiconductor..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 22, Issue 7, 870 (2002)
Analysis of Bragg Grating-Frustrated Dissimilar Two-Core Coupler
[in Chinese], [in Chinese], and [in Chinese]
The coupled mode theory for fiber coupler with dissimilar cores is extended to analyze the coupling phenomena in grating frustrated ones. The theoretical results are agreed well with the experimental results in references. Unlike the Bragg grating alone as reflective element, the main effect of the Bragg grating in theThe coupled mode theory for fiber coupler with dissimilar cores is extended to analyze the coupling phenomena in grating frustrated ones. The theoretical results are agreed well with the experimental results in references. Unlike the Bragg grating alone as reflective element, the main effect of the Bragg grating in the coupler is that it introduces a strong dispersion, making the coupler asynchronous in the spectral band of grating. It is also found that the selective spectra of the Bragg fiber coupler caused by the Bragg grating frustrated in the two dissimilar core fiber have not any sidelobe but have very weak jitters on the spectral side part and strong dips on the spectral stop band..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 22, Issue 7, 874 (2002)
Physical Optics
Dynamic Evolution of Spatial Screening-Photovoltaic Bright Soliton under Weak Amplitude Condition
[in Chinese], [in Chinese], and [in Chinese]
Neglecting both the crystal loss and the diffusion effect, both the weak light intensity spatial screening photovoltaic (SP) bright solitons in the photovoltaic photorefractive crystal with an applied electric field and their evolution characteristrcs are discussed. The analytic expression for the spatial screening phoNeglecting both the crystal loss and the diffusion effect, both the weak light intensity spatial screening photovoltaic (SP) bright solitons in the photovoltaic photorefractive crystal with an applied electric field and their evolution characteristrcs are discussed. The analytic expression for the spatial screening photovoltaic bright solitons obtained under the weak light intensity agrees well with the results obtained by the numerical calculation. This practice solves the previous problem that it is necessary to first solve the differential equation or the integral equation while numerically solving the dynamical evolution equation. The dynamical evolution of the spatial screening photovoltaic bright solitons under the condition of parameter mismatch is also discussed..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 22, Issue 7, 809 (2002)
Study on Information Entropy Representing Nonlinear Propagation of Light
[in Chinese], [in Chinese], [in Chinese], and [in Chinese]
The information entropy in quantum mechanics is introduced to represent nonlinear propagation of light within the framework of the Schroedinger formulation of light propagation. Our analytical derivation and numerical calculation show that the information entropy and its differentiation with respect to the propagation The information entropy in quantum mechanics is introduced to represent nonlinear propagation of light within the framework of the Schroedinger formulation of light propagation. Our analytical derivation and numerical calculation show that the information entropy and its differentiation with respect to the propagation direction can describe the compression and broadening of light pulse (or the focusing and diffussion of light beam), which is better than the description with pulse (beam) width and second order moments..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 22, Issue 7, 813 (2002)
Quantum Optics
Influence of Atomic Internal State Population on Its Translational Motion
Zhu Kaicheng, Zhu Zhenhe, and Tang Huiqin
The influence of atomic internal state population on its translational motion in a quantized standing wave cavity field with spatial periodic structure is investigated. On the basis of atomic two photon resonance transition and with the aid of the atomic field dressed state, the Schrodinger equations satisfied by the aThe influence of atomic internal state population on its translational motion in a quantized standing wave cavity field with spatial periodic structure is investigated. On the basis of atomic two photon resonance transition and with the aid of the atomic field dressed state, the Schrodinger equations satisfied by the atomic translational motion for two different atomic dressed internal states are built and their general relation for a spatial periodic cavity field is obtained. Under an appropriate approximation, the state vector of the whole system is derived and the study of the interaction between the atomic internal state and its translational dynamics is allowed. It is found that the distortion of the atomic translational motion wave packet is sensitive to its initial internal state population for a quantized standing wave cavity field at coherent state..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 22, Issue 7, 803 (2002)
Rapid Communications
Effect of Chirped Pulse on Phase Distortion in Second Harmonic Generation
[in Chinese], [in Chinese], [in Chinese], [in Chinese], and [in Chinese]
The effect of a chirped pulse in the process of second harmonic generation is discussed. The chirp influences the irradiance and the pulse shape of the second harmonic wave with large phase mismatch. The phase distortions of all three waves are dependant strongly on the chirp than on the phase mismatch.The effect of a chirped pulse in the process of second harmonic generation is discussed. The chirp influences the irradiance and the pulse shape of the second harmonic wave with large phase mismatch. The phase distortions of all three waves are dependant strongly on the chirp than on the phase mismatch..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 22, Issue 7, 890 (2002)
Line-Shape Changes of Na Resonance Fluorescence Due to Na-Na Collisions
[in Chinese], [in Chinese], [in Chinese], [in Chinese], [in Chinese], and [in Chinese]
In a dense Na vapor, the changes were observed in the Doppler broadened shape of the resonance fluorescence produced by the combined effect of the induced optical pumping and Na Na collisions. The observed narrowing of the fluorescence line shape was explained by a rate equation with "velocity change collision&quoIn a dense Na vapor, the changes were observed in the Doppler broadened shape of the resonance fluorescence produced by the combined effect of the induced optical pumping and Na Na collisions. The observed narrowing of the fluorescence line shape was explained by a rate equation with "velocity change collision" effect..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 22, Issue 7, 893 (2002)
Spectroscopy
Vibration Constants Measurement of Molecular Potassium Excited State by Ionization Spectrum Technique
[in Chinese], [in Chinese], [in Chinese], [in Chinese], [in Chinese], and [in Chinese]
The ionization spectra associated with the vibration energy level of 5 3Π u state of molecular potassium were observed when the potassium vapor was excited by a dye laser. The vibration constants were calculated according to the laser wavelengths. It is consistent with the theoretic result calculated by Magnier and MilThe ionization spectra associated with the vibration energy level of 5 3Π u state of molecular potassium were observed when the potassium vapor was excited by a dye laser. The vibration constants were calculated according to the laser wavelengths. It is consistent with the theoretic result calculated by Magnier and Millié within the experimental error..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 22, Issue 7, 819 (2002)
Thin Films
Design of DWDM Thin-Film Interference Filters
[in Chinese], [in Chinese], [in Chinese], [in Chinese], [in Chinese], and [in Chinese]
The basic performance of thin film interference filters used in Mux/Demux systems is presented. In response to the requirement it is important that coating materials and filter substrates must be selected carefully, and the filter designs must have excellent performance and preparation tolerance. Two design methods suiThe basic performance of thin film interference filters used in Mux/Demux systems is presented. In response to the requirement it is important that coating materials and filter substrates must be selected carefully, and the filter designs must have excellent performance and preparation tolerance. Two design methods suitable for DWDM filters are discussed..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 22, Issue 7, 794 (2002)
Synthesis of Diamond Films at Low Temperature Via Glow Plasma Assisted Hot Filament Chemical Vapor Deposition
[in Chinese], [in Chinese], [in Chinese], [in Chinese], and [in Chinese]
High quality sub microcrystalline diamond films have been synthesized in low temperature via glow plasma assisted hot filament chemical vapor deposition (GP CVD). In situ optical emission spectroscopy is applied to diagnose weak signal of GP CVD system when CH 4 and H 2 are used as the input gases, and reacting particlHigh quality sub microcrystalline diamond films have been synthesized in low temperature via glow plasma assisted hot filament chemical vapor deposition (GP CVD). In situ optical emission spectroscopy is applied to diagnose weak signal of GP CVD system when CH 4 and H 2 are used as the input gases, and reacting particles are identified for diamond growth process. The result shows that the substrate temperature for synthesizing high quality diamond films by EACVD has been reduced from 850 ℃ to (340±5) ℃ by adopting GP CVD. From experimental results, It was found that the existence of a great deal of super saturation atomic hydrogen is the key factor for producing diamond films of high quality, and the main energetic particles are CH 3, CH, CH +, H * etc. in the process of diamond films growth. Glowing of near surface may form a dipole layer, which plays a leading role in low temperature synthesis..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 22, Issue 7, 798 (2002)
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