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Contents
2002
Volume: 29 Issue 3
23 Article(s)
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Research Article
Analysis Research for Thermal Deformation of High Power CO2 Laser Mirror
[in Chinese], and [in Chinese]
Thermal conduction equation of high power CO 2 laser is established according to its running state, and the boundary conditions are given also. Analysis solution of temperature distribution of the mirror is obtained using the method of thin pieces analysis. At the end of this paper deformation of the surface of mirror Thermal conduction equation of high power CO 2 laser is established according to its running state, and the boundary conditions are given also. Analysis solution of temperature distribution of the mirror is obtained using the method of thin pieces analysis. At the end of this paper deformation of the surface of mirror is obtained..
Chinese Journal of Lasers
- Publication Date: Jan. 01, 1900
- Vol. 29, Issue 3, 201 (2002)
YBa2Cu3O7-δ Thin Film Room-temperature Laser Power Meter
[in Chinese], [in Chinese], [in Chinese], and [in Chinese]
Based on the anisotropic Seebeck effect of oxide high-T c superconductor, a new type laser power meter was designed, and the optical response of this device to the pulsed laser and the chopped laser was measured from infrared to ultraviolet. The measured singnal shows a good linear relation to the laser power in a limiBased on the anisotropic Seebeck effect of oxide high-T c superconductor, a new type laser power meter was designed, and the optical response of this device to the pulsed laser and the chopped laser was measured from infrared to ultraviolet. The measured singnal shows a good linear relation to the laser power in a limited range, and a very fast time response to the irradiating laser..
Chinese Journal of Lasers
- Publication Date: Jan. 01, 1900
- Vol. 29, Issue 3, 205 (2002)
Integrated Electrooptic M-Z Modulator with Ridge Structure in X-cut LiNbO3
[in Chinese], and [in Chinese]
An integrated electrooptic Mach-Zehnder modulator with ridge structure has been designed and fabricated by using X-cut LiNbO 3 substrate. The key techniques of LiNbO 3 wet etching and large thick electrode fabricating are contributed to form the ridge structure for the modulator. Experimental results show that the ridgAn integrated electrooptic Mach-Zehnder modulator with ridge structure has been designed and fabricated by using X-cut LiNbO 3 substrate. The key techniques of LiNbO 3 wet etching and large thick electrode fabricating are contributed to form the ridge structure for the modulator. Experimental results show that the ridge-type optical modulator has much more obvious advantages in increasing the modulation bandwidth compared with a conventional modulator with planar structure..
Chinese Journal of Lasers
- Publication Date: Jan. 01, 1900
- Vol. 29, Issue 3, 209 (2002)
Optimum Design of Chirped Mirror in the Femtosecond Pulse Laser Cavity
[in Chinese], [in Chinese], [in Chinese], and [in Chinese]
This paper introduced the basic theory and the design method of chirped mirrors. The influnce of some main factors, such as the group delay dispersion (GDD), the bandwidth of GDD, the thin film numbers and the thickness error of a single thin film on the dispersion characteristics of chirped mirror is analyzed. The choThis paper introduced the basic theory and the design method of chirped mirrors. The influnce of some main factors, such as the group delay dispersion (GDD), the bandwidth of GDD, the thin film numbers and the thickness error of a single thin film on the dispersion characteristics of chirped mirror is analyzed. The choice of the GDD and the range of GDD are the key for optimum design..
Chinese Journal of Lasers
- Publication Date: Jan. 01, 1900
- Vol. 29, Issue 3, 213 (2002)
Beam Transmission
Propagation and Spall Effect of Shock Wave Induced by Laser in Targets
[in Chinese], [in Chinese], [in Chinese], and [in Chinese]
By means of 1-D elastic-plastic hydrodynamic model and finite differential method, it is studied that formation, sustain, and decay of shock wave were induced by powerful pulsed excimer laser in target materials. By using the criterion of accumulate damage and dynamic fracture, the spall thicknesses are given in aluminBy means of 1-D elastic-plastic hydrodynamic model and finite differential method, it is studied that formation, sustain, and decay of shock wave were induced by powerful pulsed excimer laser in target materials. By using the criterion of accumulate damage and dynamic fracture, the spall thicknesses are given in aluminum and C/Ph, respectively. These calculation results are in agreement with the experimental measurements reported, and reasonably explained experimental phenomena..
Chinese Journal of Lasers
- Publication Date: Jan. 01, 1900
- Vol. 29, Issue 3, 197 (2002)
Laser Manufacturing
Study of the Laser Heat Treatment for Mould Surface
[in Chinese], [in Chinese], and [in Chinese]
The laser heat treatment for mould surface in different materials was compared. Under different condition, different results and optimal parameters were got, and good results in laser heat treatment for mould surface was obtained.The laser heat treatment for mould surface in different materials was compared. Under different condition, different results and optimal parameters were got, and good results in laser heat treatment for mould surface was obtained..
Chinese Journal of Lasers
- Publication Date: Jan. 01, 1900
- Vol. 29, Issue 3, 271 (2002)
Microstructure and Property of Laser Gas Nitriding on γ-TiAl Alloy
[in Chinese], [in Chinese], [in Chinese], [in Chinese], [in Chinese], and [in Chinese]
Composite modification layer on γ-TiAl alloy could be available by laser gas nitriding technique which was reinforced by nitrides. The microstructure characteristics of nitriding layer were investigated through SEM, XRD and TEM examination. It is consisted of α, γ, TiN and Ti 2AlN and is inhomogeneous distributed throuComposite modification layer on γ-TiAl alloy could be available by laser gas nitriding technique which was reinforced by nitrides. The microstructure characteristics of nitriding layer were investigated through SEM, XRD and TEM examination. It is consisted of α, γ, TiN and Ti 2AlN and is inhomogeneous distributed throughout the nitriding zone. The maximum hardness value reaches to 1000 kg/mm 2 and is double that of the matrix one. The effect of nitriding on micro-hardness was also discussed..
Chinese Journal of Lasers
- Publication Date: Jan. 01, 1900
- Vol. 29, Issue 3, 277 (2002)
Numerical Simulation on the Micro-scale Bending Induced by Pulsed Laser Beam
[in Chinese], and [in Chinese]
In this paper, the micro-scale bending process and mechanism were studied numerically with ANSYS and a FEM code, which could be used to investigate thermal mechanical coupling and finite deformation impacting problem. The distributions and evolution of temperature, stresses and plastic strain were shown in the paper. AIn this paper, the micro-scale bending process and mechanism were studied numerically with ANSYS and a FEM code, which could be used to investigate thermal mechanical coupling and finite deformation impacting problem. The distributions and evolution of temperature, stresses and plastic strain were shown in the paper. At the same time, the effects of laser beam parameters and materials constants on the bending angle were discussed, and compared well with the experimental observations..
Chinese Journal of Lasers
- Publication Date: Jan. 01, 1900
- Vol. 29, Issue 3, 281 (2002)
A New Method of Resistless Photochemical Etching for Silicon Wafer
[in Chinese], [in Chinese], and [in Chinese]
A new method of resistless photochemical etching for silicon wafer is developed, which is using hydrogen peroxide (H 2O 2) and hydrogen fluoride (HF) as activated species, ArF ultraviolet laser as a photon source. Silicon wafer can be directly etched without photo-resists. When the concentration ratio of H 2O 2/HF is 1A new method of resistless photochemical etching for silicon wafer is developed, which is using hydrogen peroxide (H 2O 2) and hydrogen fluoride (HF) as activated species, ArF ultraviolet laser as a photon source. Silicon wafer can be directly etched without photo-resists. When the concentration ratio of H 2O 2/HF is 1.3, the optimized etching was found. At the energy density of 29 mJ/cm 2 as well as the shot numbers of 10000, the maximum etching depth of 210 nm was obtained..
Chinese Journal of Lasers
- Publication Date: Jan. 01, 1900
- Vol. 29, Issue 3, 286 (2002)
Laser Physics
Study on MOVPE Growth of 1.3 μm Uncooled AlGaInAs/InP Strain-compensated Quantum Well Lasers
[in Chinese], [in Chinese], [in Chinese], [in Chinese], and [in Chinese]
AlGaInAs strain-compensated quantum wells have been grown by LP-MOVPE. By X-ray diffraction, photoluminescence and SIMS, the properties of the materials and the oxygen concentration in AlGaInAs materials are analyzed. A high quality (PL FWHM=26 meV: room temperature) AlGaInAs strain-compensated quantum well through optAlGaInAs strain-compensated quantum wells have been grown by LP-MOVPE. By X-ray diffraction, photoluminescence and SIMS, the properties of the materials and the oxygen concentration in AlGaInAs materials are analyzed. A high quality (PL FWHM=26 meV: room temperature) AlGaInAs strain-compensated quantum well through optimized MOVPE process is obtained. By the wafers, the 1.3 μm uncooled AlGaInAs strain-compensated quantum well lasers have been fabricated. The results of the laser chips are: 1290 nm≤λ≤1330 nm, I th(25℃)≤15 mA, I th(85℃)≤25 mA and Δη ex(25～85℃)≤1.0 dB..
Chinese Journal of Lasers
- Publication Date: Jan. 01, 1900
- Vol. 29, Issue 3, 193 (2002)
Multiphoton Ionization Mass Spectra Study of Tetramethylsilane at 355 nm Laser Radiation
[in Chinese], [in Chinese], and [in Chinese]
Multiphoton ionization (MPI) mass spectra distributions of tetramethylsilane in gaseous phase are investigated using a quadrupole mass spectrometer and a pulsed molecular beam at 355 nm laser radiation. The dependence of the signal intensity of the ions Si(CH 3) + n (n=1,2,3,4) and Si + on laser power is measured. The Multiphoton ionization (MPI) mass spectra distributions of tetramethylsilane in gaseous phase are investigated using a quadrupole mass spectrometer and a pulsed molecular beam at 355 nm laser radiation. The dependence of the signal intensity of the ions Si(CH 3) + n (n=1,2,3,4) and Si + on laser power is measured. The fractions of signal Si(CH 3) + n(n=1,2,3,4) and Si + vs. laser intensity are obtained. According to these, the possible MPI channels and the chemical kinetics mechanisms of this molecule are discussed. The conclusion is gained that Si + ions might be mainly produced via a sequential photo-dissociation to form Si atoms first and followed by a multiphoton ionization of Si atoms, Si(CH 3) + n(n=1,2,3) ions might be mainly produced from self-ionization of neutral fragments Si(CH 3) n, and the Si(CH 3) + 4 ions might be produced from (3+1) ionization of parent molecules..
Chinese Journal of Lasers
- Publication Date: Jan. 01, 1900
- Vol. 29, Issue 3, 218 (2002)
Propagation of Hermite-Gaussian Beams through a Misaligned First-order Optical System and Decentered Hermite-Gaussian Beams
[in Chinese], and [in Chinese]
Propagation properties of Hermite-Gaussian beams through a misaligned first-order ABCD optical systems are studied using the generalized Huygens-Fresnel diffraction integral, augmented matrix and Wigner distribution function methods. It is shown that, as a Hermite-Gaussian beam passes through the misaligned first-orderPropagation properties of Hermite-Gaussian beams through a misaligned first-order ABCD optical systems are studied using the generalized Huygens-Fresnel diffraction integral, augmented matrix and Wigner distribution function methods. It is shown that, as a Hermite-Gaussian beam passes through the misaligned first-order ABCD optical system, the closed property is not preserved. The action of the misaligned first-order ABCD optical system turns the output beam into a more general class of beam having the decentered property, which can be called the decentered Hermite-Gaussian beam. The usual Hermite-Gaussian beam and decentered Gaussian beam can be regarded as its special cases..
Chinese Journal of Lasers
- Publication Date: Jan. 01, 1900
- Vol. 29, Issue 3, 223 (2002)
Materials and Thin Films
Spectral Properties of ErCa4O(BO3)3 Crystal
[in Chinese], [in Chinese], [in Chinese], [in Chinese], [in Chinese], [in Chinese], and [in Chinese]
The transparent and homogeneous ErCa 4O(BO 3) 3 (ECOB) crystal is grown by Czochralski method. The room temperature absorption spectra have been measured and compared with that of 0.1 mol ErCl 3 solution. According to Judd-Ofelt theory, the spectral strength parameters: Ω 2=1.673×10 -20 cm 2, Ω 4=1.356×10 -20The transparent and homogeneous ErCa 4O(BO 3) 3 (ECOB) crystal is grown by Czochralski method. The room temperature absorption spectra have been measured and compared with that of 0.1 mol ErCl 3 solution. According to Judd-Ofelt theory, the spectral strength parameters: Ω 2=1.673×10 -20 cm 2, Ω 4=1.356×10 -20 cm 2, Ω 6=0.156×10 -20 cm 2 of Er 3+ ion have been fitted. The radiative transition probabilities A J,J′, oscillator strengths f J,J′, radiative lifetime τ and the branching ratio β J′ have been calculated. From these parameters, the properties and applications were discussed..
Chinese Journal of Lasers
- Publication Date: Jan. 01, 1900
- Vol. 29, Issue 3, 227 (2002)
Application of N31 Type Nd:phosphate Glass Amplifie on Shenguang-Ⅱ
[in Chinese], [in Chinese], [in Chinese], [in Chinese], and [in Chinese]
After Shenguang-Ⅱ system is improved particulaly on beam quality the figure of filler reaches about 50%. The beam spatial distrubution is uniform. New N 31 type phosphate glass are used, the fluorescence life is increased from 250 μs to 330 μs. The gain ability is increased. The gain of 6 disks N 31 type phosphate glasAfter Shenguang-Ⅱ system is improved particulaly on beam quality the figure of filler reaches about 50%. The beam spatial distrubution is uniform. New N 31 type phosphate glass are used, the fluorescence life is increased from 250 μs to 330 μs. The gain ability is increased. The gain of 6 disks N 31 type phosphate glass compared with the gain of 8 disks N 21 type phosphate glass, the gain increased about 10%..
Chinese Journal of Lasers
- Publication Date: Jan. 01, 1900
- Vol. 29, Issue 3, 230 (2002)
Study on Crystal Growth and Properties of Ce:LiM(M=Ca,Sr)AlF6 Crystals
[in Chinese], [in Chinese], [in Chinese], and [in Chinese]
Crystal growth of Ce 3+ doped LiM(M=Ca, Sr)AlF 6 mixed crystal were successfully carried out in CF 4 atmosphere. The UV absorption spectra and the effective segregation coefficients of Ce 3+ ions in these crystals were measured and reported. Ce∶LiSr 0.8Ca 0.2AlF 6 crystal shows a broaden absorption band in the wavelengCrystal growth of Ce 3+ doped LiM(M=Ca, Sr)AlF 6 mixed crystal were successfully carried out in CF 4 atmosphere. The UV absorption spectra and the effective segregation coefficients of Ce 3+ ions in these crystals were measured and reported. Ce∶LiSr 0.8Ca 0.2AlF 6 crystal shows a broaden absorption band in the wavelength range of 240～280 nm, and the effective segregation coefficient of Ce 3+ ions in the mixed crystals is 0.037. It is believed that the broadening of the absorption band in the Ce∶LiSr 0.8Ca 0.2AlF 6 crystal was caused by substitution of Ce 3+ ions for divalent ions in the Colquiriite structure crystals..
Chinese Journal of Lasers
- Publication Date: Jan. 01, 1900
- Vol. 29, Issue 3, 233 (2002)
Measurement and Metrology
Research on High Power Laser Beam and Focus Power Intensity Distribution Directly Measuring Instrument
[in Chinese], [in Chinese], [in Chinese], [in Chinese], [in Chinese], and [in Chinese]
Using the method of rotating needle pinhole, the measuring system which can directly measure the high dense laser transverse intensity distribution of laser beams/focus for laser processing is developed. The mathematical and physical models of measured laser beams/focus propagation in needle pinhole are established. AcUsing the method of rotating needle pinhole, the measuring system which can directly measure the high dense laser transverse intensity distribution of laser beams/focus for laser processing is developed. The mathematical and physical models of measured laser beams/focus propagation in needle pinhole are established. According to the calculation, the system parameters, including aperture of needle pinhole, dimension of propagation channel, dot number of sampling, are given. A new measuring system is designed. The measuring of high power laser beams/focus by this system is realized. The calculation results are of agreement with the measuring results. The instrument can measure CO 2 and YAG laser, measured power larger than 10 kW, maximal measured power density up to 10 7 W/cm 2, measured laser beam maximal diameter is 60 mm, measured laser focus minimal diameter smaller than 0.5 mm..
Chinese Journal of Lasers
- Publication Date: Jan. 01, 1900
- Vol. 29, Issue 3, 257 (2002)
Multi-beam Confocal System Using Pinhole Array
[in Chinese], [in Chinese], [in Chinese], and [in Chinese]
The 500×500 pinhole array is used in the multi-beam confocal system for 3D measurement. The equipment needn't mechanical rotation, thus it is simple in the mechanism, also the measuring field is larger. With the interpolation technique, the 3D profile can be got quickly with high precision.The 500×500 pinhole array is used in the multi-beam confocal system for 3D measurement. The equipment needn't mechanical rotation, thus it is simple in the mechanism, also the measuring field is larger. With the interpolation technique, the 3D profile can be got quickly with high precision..
Chinese Journal of Lasers
- Publication Date: Jan. 01, 1900
- Vol. 29, Issue 3, 263 (2002)
Study on the Precision Energy Measurement System for High Power Laser
[in Chinese], [in Chinese], [in Chinese], [in Chinese], [in Chinese], and [in Chinese]
A full-automatic precision energy measurement system on small signal was described in detail, which was used for eight beams' power balance in Shenguang Ⅱ. An assembly attenuator of half-wave plate and polarizers is used to check up the performance of the system. The precision of stability precedes 1% (rms). And thA full-automatic precision energy measurement system on small signal was described in detail, which was used for eight beams' power balance in Shenguang Ⅱ. An assembly attenuator of half-wave plate and polarizers is used to check up the performance of the system. The precision of stability precedes 1% (rms). And the measuring range covers three magnitudes. It enlarges the measuring range of the original measurement facility of Shenguang Ⅱ..
Chinese Journal of Lasers
- Publication Date: Jan. 01, 1900
- Vol. 29, Issue 3, 267 (2002)
Optical Communication
Beat Phenomena and Its Suppression in Cascaded Ring-cavity Gain-clamping EDFAs
[in Chinese], [in Chinese], and [in Chinese]
Analytical expressions, basic rules and physical interpretation of beat phenomena during channel add/drop in cascaded ring-cavity GC-EDFAs are obtained and agree well with experimental results. Measures to depress or avoid this beat phenomena are proposed for systems using tone modulation technique, where this beat pheAnalytical expressions, basic rules and physical interpretation of beat phenomena during channel add/drop in cascaded ring-cavity GC-EDFAs are obtained and agree well with experimental results. Measures to depress or avoid this beat phenomena are proposed for systems using tone modulation technique, where this beat phenomena may lead to severe BER degradation..
Chinese Journal of Lasers
- Publication Date: Jan. 01, 1900
- Vol. 29, Issue 3, 243 (2002)
Integrated Optical TE/TM Polarization Splitter on LiNbO3 Using Titanium Diffusion
[in Chinese], [in Chinese], [in Chinese], [in Chinese], and [in Chinese]
A advanced polarization splitter with directional coupler has been proposed for use in integrated optical circuits on LiNbO 3, and a detailed theoretical analysis has been given. The power splitting ratio of the polarization splitter has been calculated by using 2D-beam propagation method(BPM). In theory, the power splA advanced polarization splitter with directional coupler has been proposed for use in integrated optical circuits on LiNbO 3, and a detailed theoretical analysis has been given. The power splitting ratio of the polarization splitter has been calculated by using 2D-beam propagation method(BPM). In theory, the power splitting ratioes of the TM mode and TE mode through the splitter are both above 40 dB. At the same time, some polarization splitters have been actually fabricated. And the power splitting ratioes of the TM mode and TE mode are 28 dB and 25 dB, respectively..
Chinese Journal of Lasers
- Publication Date: Jan. 01, 1900
- Vol. 29, Issue 3, 249 (2002)
Asymmetrical Self-imaging Effects of MMI Devices with Two-dimensional Confinement
[in Chinese], [in Chinese], [in Chinese], and [in Chinese]
The self-imaging effects of multi-mode interference (MMI) devices with two-dimensional confinement are given by using guided-mode propagation analysis method. This paper firstly discusses the asymmetrical characteristic MMI devices with two-dimensional confinement in detail. At the same time, the three-dimensional all-The self-imaging effects of multi-mode interference (MMI) devices with two-dimensional confinement are given by using guided-mode propagation analysis method. This paper firstly discusses the asymmetrical characteristic MMI devices with two-dimensional confinement in detail. At the same time, the three-dimensional all-vector finite difference beam propagation method (BPM) is used to confirm the analytical results..
Chinese Journal of Lasers
- Publication Date: Jan. 01, 1900
- Vol. 29, Issue 3, 253 (2002)
Spectroscopy
A Method of Evaluating the Roughness of a Co/C Multi-layer Film
[in Chinese], and [in Chinese]
Stearns' scattering method is introduced in this paper, which describes the scattering of a single non-ideal interface and is applicable for soft X-ray short wavelength region. It is then extended to multi-layer structure and uses a mathematical modal from Stearns' method to describing the multi-layer interfaceStearns' scattering method is introduced in this paper, which describes the scattering of a single non-ideal interface and is applicable for soft X-ray short wavelength region. It is then extended to multi-layer structure and uses a mathematical modal from Stearns' method to describing the multi-layer interface roughness at soft X-ray short wavelength region (1～10nm). Under the framework of this theory, the interface roughness of a Co/C multi-layer mirror with the wavelength of 4.77 nm is analyzed. The root-mean-square roughness of the multi-layer interface of the mirror is 0.7 nm..
Chinese Journal of Lasers
- Publication Date: Jan. 01, 1900
- Vol. 29, Issue 3, 236 (2002)
Optical Constants of a New Soluble Subphthalocyanine Spin-coated Thin Film
[in Chinese], and [in Chinese]
A new soluble subphthalocyanine (bromoboron trineopentoxy-subphthalocyanine) thin film was prepared by spin-coating on a single-crystal silicon substrate. The ellipsometric spectra of this film were investigated with an improved automatic ellipsometer. The complex refractive index, dielectric functions and absorption cA new soluble subphthalocyanine (bromoboron trineopentoxy-subphthalocyanine) thin film was prepared by spin-coating on a single-crystal silicon substrate. The ellipsometric spectra of this film were investigated with an improved automatic ellipsometer. The complex refractive index, dielectric functions and absorption coefficient of this film in the 300～800 nm wavelength region were given. The spectra were explained and discussed as well..
Chinese Journal of Lasers
- Publication Date: Jan. 01, 1900
- Vol. 29, Issue 3, 239 (2002)
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