Journals >Chinese Journal of Lasers
Contents
1996
Volume: 23 Issue 4
20 Article(s)
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Research Article
Measurement of the Thickess and Dielectric Constants of Metal Films by Surface Plasma Wave Excited with One Wavelength
[in Chinese], [in Chinese], [in Chinese], and [in Chinese]
In this paper, the surface plasma wave (SPW) on the interface of medal-electricmedium was excited with one wavelength by using the angle scanning ATR method and thethickness and dielectric constants of metal films were measured by a nonlinear least-squarecure-fitting method.In this paper, the surface plasma wave (SPW) on the interface of medal-electricmedium was excited with one wavelength by using the angle scanning ATR method and thethickness and dielectric constants of metal films were measured by a nonlinear least-squarecure-fitting method..
Chinese Journal of Lasers
- Publication Date: Jan. 01, 1900
- Vol. 23, Issue 4, 338 (1996)
The 3-D Stress Field Measurement with Phase-shift Isodyne
[in Chinese], [in Chinese], and [in Chinese]
An analysis method of whole field measurement of indyne flinges is presented.This method is based on three pattern phase-shift techniques.The obtained phase mapcorresponds to stresses components.Phase-shift indyne is ugh to determine stresses incomposite structure, in particular,the stresses at internal discontinuitiesAn analysis method of whole field measurement of indyne flinges is presented.This method is based on three pattern phase-shift techniques.The obtained phase mapcorresponds to stresses components.Phase-shift indyne is ugh to determine stresses incomposite structure, in particular,the stresses at internal discontinuities and thedelaminating stresses. The comopite structure beam is liken as an illustrative example in thepoper, with particular attention given to the 3-D stress effects. It is demonstrated that the isodyne method allows the determination of the 3-D stress field in the composite structure..
Chinese Journal of Lasers
- Publication Date: Jan. 01, 1900
- Vol. 23, Issue 4, 343 (1996)
Study of Ultrafast Relaxation of Laser Dye in Solutionby Femtosecond Laser
[in Chinese], [in Chinese], [in Chinese], [in Chinese], [in Chinese], and [in Chinese]
A number of techniques have been developed for the study of ultrafast processesof molecules in condensed phase.With a home-made femtosecond laser oscillator we havedeveloped a new method called "Femtosecond Time-Resolved Stimulated Emission PumpingFluorescence Depletion, FSTR-SEP FD" to study the ultra fast rA number of techniques have been developed for the study of ultrafast processesof molecules in condensed phase.With a home-made femtosecond laser oscillator we havedeveloped a new method called "Femtosecond Time-Resolved Stimulated Emission PumpingFluorescence Depletion, FSTR-SEP FD" to study the ultra fast relaxation of LDS821 laserdye in different solvents..
Chinese Journal of Lasers
- Publication Date: Jan. 01, 1900
- Vol. 23, Issue 4, 349 (1996)
Coupled Wave Analysis of an Optical Refractive Index TaperedFiber Coupler by UV Irradiation
[in Chinese], [in Chinese], [in Chinese], [in Chinese], [in Chinese], and [in Chinese]
We discussed the mode coupling in an optical fiber tapered coupler with itsrefractive index gradually changins along its propagation axis caused by photo-inducedrefractive effect. Under scalar approximation, the field in the stead index fiber andparabolic-index fiber tapers is expressed in local normal modes to analyzeWe discussed the mode coupling in an optical fiber tapered coupler with itsrefractive index gradually changins along its propagation axis caused by photo-inducedrefractive effect. Under scalar approximation, the field in the stead index fiber andparabolic-index fiber tapers is expressed in local normal modes to analyze the coupling of thefundamental mode to its reflected one in opposite direction and high-order ones in codirection. The numeric resultS for two different taper profiles in step-index fiber show that the couplings to the reflected mode and the high-order modes are relatively small provided the change is gradual, and the fundamental mode has the capability of excellent transmission which can adjust itself adiabatically to the reflective index change..
Chinese Journal of Lasers
- Publication Date: Jan. 01, 1900
- Vol. 23, Issue 4, 353 (1996)
Holography and Information Processing
A Simple Method of Making Two-step Rainbow Hologram with High Efficiency and High Brightness
[in Chinese], and [in Chinese]
A simple method of making two-step rainbow hologram with high efficiency andhigh brightness is proposed. In the method a slit used to recotd the two-stop rainbowhologram is transferred to primary hologram, so as to use fully its area. The method givenin this paper has practical value for embossing hologram which uses pA simple method of making two-step rainbow hologram with high efficiency andhigh brightness is proposed. In the method a slit used to recotd the two-stop rainbowhologram is transferred to primary hologram, so as to use fully its area. The method givenin this paper has practical value for embossing hologram which uses photore Sist as therecording material. Satisfactory results are obtained in corresponding experiments..
Chinese Journal of Lasers
- Publication Date: Jan. 01, 1900
- Vol. 23, Issue 4, 359 (1996)
Laser Manufacturing
Study of Activation of Carbon Electrodes by Laser Pulses
[in Chinese], [in Chinese], [in Chinese], and [in Chinese]
Laser pulses(1.06 μm)were used to irradiate glassy carbon electrodes (GCE)and carbon fibre electrodes.The activity of surface can be effectively improved after carbonelectrodes have been treated.The rate of electrode reaction for Fe3+/2+ and ascorbic acid onelectrodes was dramatically increased.We suggest that the resuLaser pulses(1.06 μm)were used to irradiate glassy carbon electrodes (GCE)and carbon fibre electrodes.The activity of surface can be effectively improved after carbonelectrodes have been treated.The rate of electrode reaction for Fe3+/2+ and ascorbic acid onelectrodes was dramatically increased.We suggest that the result is associated, under theirradiation of very short and high power laser pulses, with the removal of inactive layers,change of microstructure and exposure of more active sites on the carbon electrodes..
Chinese Journal of Lasers
- Publication Date: Jan. 01, 1900
- Vol. 23, Issue 4, 366 (1996)
Numerical Simulation of Transient Fluid Flow and Temperature FieldDuring Pulsed Nd: YAG Laser Surface Remelting
[in Chinese], [in Chinese], and [in Chinese]
Based on one region continuum model for alloy phase transformation, thetransient fluid flow and temperature fields for pulsed Nd:YAG laser surface remelting havebeen calculated by using numerical simulation method. The absorption (melting process) and release (solidifying process) of latent heat, the heat loss by alloyBased on one region continuum model for alloy phase transformation, thetransient fluid flow and temperature fields for pulsed Nd:YAG laser surface remelting havebeen calculated by using numerical simulation method. The absorption (melting process) and release (solidifying process) of latent heat, the heat loss by alloy elements vaporization, radiation, and natural convection are included in the solving conditions of the energyequation. The thermocapillary and buoyancy driven flow are included in the solution of momentum equations. According to the experimental condition, the melted region shapes and sizes are calculated for 1Cr18Ni9Ti stainless steel in pulsed Nd:YAG laser surface remelting of lower frequency and a shot pulse duration. It is revealed that a two dimensional axisymmetric model can properly simulate the transient fluid flow in the melted region and the melted region shapes for either individual pulse or a series of pulsed overlapping remelting regions..
Chinese Journal of Lasers
- Publication Date: Jan. 01, 1900
- Vol. 23, Issue 4, 369 (1996)
Backscattering within a Passive Resonator Laser Gyroscope
[in Chinese]
That in a closed-loop passive ring resonator laser gyroscope, the bockscatteringfrom cavity mirrors within the resonator, not only can cause lock-in effect, but also cancause mode-pulling effect, is demonstrated in theory. bential measures for the eliminationof the lock-in effect are discussed.That in a closed-loop passive ring resonator laser gyroscope, the bockscatteringfrom cavity mirrors within the resonator, not only can cause lock-in effect, but also cancause mode-pulling effect, is demonstrated in theory. bential measures for the eliminationof the lock-in effect are discussed..
Chinese Journal of Lasers
- Publication Date: Jan. 01, 1900
- Vol. 23, Issue 4, 376 (1996)
On Mechanism of Laser Welding of Cemented Carbides and Steel
[in Chinese], and [in Chinese]
A mechanism is put forward of laser dip soldering of steel and cemented carbides.The influence of structure and composition change of the welding seam on the quality ofwelding is discussed. This paper also Presents the state change of WC and Co in the laserwelding process and its effect on welding quality. The metallurA mechanism is put forward of laser dip soldering of steel and cemented carbides.The influence of structure and composition change of the welding seam on the quality ofwelding is discussed. This paper also Presents the state change of WC and Co in the laserwelding process and its effect on welding quality. The metallurgical welding result withoutstrap fissures is given..
Chinese Journal of Lasers
- Publication Date: Jan. 01, 1900
- Vol. 23, Issue 4, 381 (1996)
Laser Physics
Investigation of "Shengguang-Ⅱ" Main Amplifier
[in Chinese], [in Chinese], [in Chinese], [in Chinese], and [in Chinese]
This paper reviews a new double-bass coaxial amplifier in 2×2 array of"Shengguang-Ⅱ". Main amplifier with a net aperture φ200 mm.The experimental andtheoretical results of a single beamline are given.This paper reviews a new double-bass coaxial amplifier in 2×2 array of"Shengguang-Ⅱ". Main amplifier with a net aperture φ200 mm.The experimental andtheoretical results of a single beamline are given..
Chinese Journal of Lasers
- Publication Date: Jan. 01, 1900
- Vol. 23, Issue 4, 289 (1996)
Investigation of Multi-wavelength Tunable Ti:sapphire Femtosecond Laser
[in Chinese], [in Chinese], [in Chinese], [in Chinese], and [in Chinese]
A multi-wavelength tunable self-mode-locked Ti:sapphire laser has beenconstructed that synchronously gcncratcs femtosecond pulse trains at two independentwavelength regions or three. Pulses as short as 48 fs with a 70 mW average output powerand a central tvavelength separation adjustable between 26 nm and 49 nm have beA multi-wavelength tunable self-mode-locked Ti:sapphire laser has beenconstructed that synchronously gcncratcs femtosecond pulse trains at two independentwavelength regions or three. Pulses as short as 48 fs with a 70 mW average output powerand a central tvavelength separation adjustable between 26 nm and 49 nm have beenproduced by using correspondent apertures or slits. This laser can be tuned from 750 nm to 830 nm..
Chinese Journal of Lasers
- Publication Date: Jan. 01, 1900
- Vol. 23, Issue 4, 295 (1996)
High Frequency Modulated RF Excited Waveguide CO2Laser
[in Chinese], [in Chinese], and [in Chinese]
In this paper, a gain switching modulated RF excited laser is reported, withwhich we have obtained the high frequency of up to 200 kHz modulated laser output. Whenthe modulation frequency is below 20 kHz, superpulse laser outputs have been obtained.In this paper, a gain switching modulated RF excited laser is reported, withwhich we have obtained the high frequency of up to 200 kHz modulated laser output. Whenthe modulation frequency is below 20 kHz, superpulse laser outputs have been obtained..
Chinese Journal of Lasers
- Publication Date: Jan. 01, 1900
- Vol. 23, Issue 4, 300 (1996)
Stability Limit Conditions of Semiconductor Lasers with a Strongly Coupled External Cavity
[in Chinese], [in Chinese], and [in Chinese]
The stability properties of semiconductor lasers strongly coupled to an externalcavity are theoretically analyzed.A strong feedback factor approximation is introduced tothe rate equations of external cavity semiconductor lasers.Through a gain-rate-frequencyellipe drawing,we get a result that there exists a theoretical The stability properties of semiconductor lasers strongly coupled to an externalcavity are theoretically analyzed.A strong feedback factor approximation is introduced tothe rate equations of external cavity semiconductor lasers.Through a gain-rate-frequencyellipe drawing,we get a result that there exists a theoretical limit condition on the stabilityof given semiconductor lasers with a strongly coupled external cavity. Technical methodscan not surpass this limit condition after the parameters of laser are given. We also concluded that stronger feedback and shorter length of the external cavity are beneficial to improving the stability of lasers..
Chinese Journal of Lasers
- Publication Date: Jan. 01, 1900
- Vol. 23, Issue 4, 303 (1996)
Study of a CuCl Vapor Laser Tube
[in Chinese], [in Chinese], [in Chinese], and [in Chinese]
A new type CuCl vapor laser discharge tube is introduced.The internal tube isbamboo shaped designed with several sections.This design results in the uniform andeffective excitation in the whole discharge tube and it is also vsry helpful for reducing theParticle deposition rate on windows.Therefore the output laser poweA new type CuCl vapor laser discharge tube is introduced.The internal tube isbamboo shaped designed with several sections.This design results in the uniform andeffective excitation in the whole discharge tube and it is also vsry helpful for reducing theParticle deposition rate on windows.Therefore the output laser power, the operationstability and lifetime of the laser tube are increased obviously.The techniques and majorparameters are also described briefly..
Chinese Journal of Lasers
- Publication Date: Jan. 01, 1900
- Vol. 23, Issue 4, 307 (1996)
Nonlinear Theory of Electromagnetically Induced Transparency
[in Chinese], and [in Chinese]
The nonlinear behavior of electromapnetically induced transparency in an excitedstate doublet three-level atomic system has been studied.It is shown that although thetransparency to a probe field still persists at zero detuning,the dispersion of the mediumdecreases because of the nonlinear effect of the probe field,andThe nonlinear behavior of electromapnetically induced transparency in an excitedstate doublet three-level atomic system has been studied.It is shown that although thetransparency to a probe field still persists at zero detuning,the dispersion of the mediumdecreases because of the nonlinear effect of the probe field,and the group velocity becomeslarger as the probe field intensity increases..
Chinese Journal of Lasers
- Publication Date: Jan. 01, 1900
- Vol. 23, Issue 4, 311 (1996)
Study on Anomalous Skin Effect with Fourier Transformation
[in Chinese], and [in Chinese]
In this peper, we present a new method based on Fourier transformation to studythe skin effects in the interaction of short laser pulses with dense plasmas.With thismethod.the field amplitude in a plasma can be lepresented explicitly in terms of electricconductivity. The normal and anomalous skin effects can be describIn this peper, we present a new method based on Fourier transformation to studythe skin effects in the interaction of short laser pulses with dense plasmas.With thismethod.the field amplitude in a plasma can be lepresented explicitly in terms of electricconductivity. The normal and anomalous skin effects can be described through one equationby omitting the plasma dispersion function or by including it in the conductivity. The resultsare in Weement with other Publications(e.g. J. P. Matte and K. Aguenaou, Phys. Rev. A, 1992, 45: 2558) for equivalent parameters. But for deeper positions inside a target, which have not been studied get, we have found that the field amplitude is considerably enhanced due to the anomalous skin effect, even for constant collision frequency. In addition, we also present some calculation results of anomalous skin effect for different collision frequencies..
Chinese Journal of Lasers
- Publication Date: Jan. 01, 1900
- Vol. 23, Issue 4, 315 (1996)
Paraxial Riemannian Geometrical OpticsⅢ. Statistical Behaviors of Beam Propagation
[in Chinese], [in Chinese], and [in Chinese]
In this paper,by using the Hermite-Gaussian expansion method,we analyse thestatistical propagation behaviors of a Paraxial beam and obtain the propagation parameters ofthe equivalent Gaussian beam which can describe the propagation behaviors of the Paraxialbeam.These results can be used in the geometrical description fIn this paper,by using the Hermite-Gaussian expansion method,we analyse thestatistical propagation behaviors of a Paraxial beam and obtain the propagation parameters ofthe equivalent Gaussian beam which can describe the propagation behaviors of the Paraxialbeam.These results can be used in the geometrical description for the propagation of aperaxial beam..
Chinese Journal of Lasers
- Publication Date: Jan. 01, 1900
- Vol. 23, Issue 4, 320 (1996)
Observation of Vaccum Ultraviolet Radiation from Krypton Fluoride Ionic Excimer
[in Chinese], [in Chinese], and [in Chinese]
It is reported that VUV continuum from a new kind of ionic excimer, kryptonfluoride ionic excimer, was observed in experiment. The peak of radiation is near 148 nm, which is coincident with the theoretical results.It is reported that VUV continuum from a new kind of ionic excimer, kryptonfluoride ionic excimer, was observed in experiment. The peak of radiation is near 148 nm, which is coincident with the theoretical results..
Chinese Journal of Lasers
- Publication Date: Jan. 01, 1900
- Vol. 23, Issue 4, 328 (1996)
Variation of the Effective Refractive Index Profile in Ti:LiNbO_3 Strip Waveguide with Diffusion Parameters
[in Chinese], [in Chinese], [in Chinese], and [in Chinese]
In designing integrated optical devices the usual practice is to reduce the problemto 2-D by means of the effective-index method.In this paper we have derived a reducedfotmula foe effective refractive index in Ti:LiNbO3 strip waveguides,calculated thevariations of the profile of effective refractive index with diffusioIn designing integrated optical devices the usual practice is to reduce the problemto 2-D by means of the effective-index method.In this paper we have derived a reducedfotmula foe effective refractive index in Ti:LiNbO3 strip waveguides,calculated thevariations of the profile of effective refractive index with diffusion parameters and discussedthe results,so as to provide a firm basis for the optimal control of the diffusion condition..
Chinese Journal of Lasers
- Publication Date: Jan. 01, 1900
- Vol. 23, Issue 4, 333 (1996)
Materials and Thin Films
Absorption and Oxygen-annealing Characterizationof Cr4+in Cr,Ca:Y3Al5O12Crystals
[in Chinese], [in Chinese], [in Chinese], [in Chinese], [in Chinese], and [in Chinese]
Single crystals of Cr,Ca:Y3Al5O12(YAG)were grown by the Czochralski (CZ) method. The aborption characterization of both as-grown and oxygen-annealedcryStals was carried out and compered with each other. Every absorption peak of Cr4+ and Cr3+ increased in intensity by annealing. It's also found that the main band poSingle crystals of Cr,Ca:Y3Al5O12(YAG)were grown by the Czochralski (CZ) method. The aborption characterization of both as-grown and oxygen-annealedcryStals was carried out and compered with each other. Every absorption peak of Cr4+ and Cr3+ increased in intensity by annealing. It's also found that the main band position of Cr 3+ was red shifted. These phenomena and formation mechanism were analyscd anddiscuss..
Chinese Journal of Lasers
- Publication Date: Jan. 01, 1900
- Vol. 23, Issue 4, 363 (1996)
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