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RSS1998 Vol. 22, No. 4
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1998, 22(4): 193-198.
[Abstract]
[PDF 909KB]
Abstract:
In this paper,some recent advances in high power solid state lasers and related technologies,such as the high power diode pumped solid state laser(DPL),DPL drivers for inertial confinement fusion and inertial fusion energy,terawatt and petawatt ultrahigh brightness laser sources,as well as slab laser amplifiers etc.have been reviewed and analyzed.
In this paper,some recent advances in high power solid state lasers and related technologies,such as the high power diode pumped solid state laser(DPL),DPL drivers for inertial confinement fusion and inertial fusion energy,terawatt and petawatt ultrahigh brightness laser sources,as well as slab laser amplifiers etc.have been reviewed and analyzed.
1998, 22(4): 199-202.
Abstract:
First we discuss the effect of the parameter selection on the reconstruction of phase space through the analysis of chaotic signal and the signal received by laser underwater target detection system.Then we analysis the phase space of cosine,random,chaos and experiment signal,and find that the phase space of the experiment signal is similar with chaos phase space,but different from the random phase space.
First we discuss the effect of the parameter selection on the reconstruction of phase space through the analysis of chaotic signal and the signal received by laser underwater target detection system.Then we analysis the phase space of cosine,random,chaos and experiment signal,and find that the phase space of the experiment signal is similar with chaos phase space,but different from the random phase space.
1998, 22(4): 203-206.
Abstract:
In this paper,starting from the rate equation of a quasi three level system,the rate equation of diode pumped solid state lasers has been derived.A method for calculating the output power in longitudinally diode pumped CW lasers has been proposed,which is represented as a function of the two parameters:the active medium length and transmissivity.The optimal design procedure has been found.Numerical calculations have shown a good consistency with our experimental result and the data in Refs. [3] and [4].
In this paper,starting from the rate equation of a quasi three level system,the rate equation of diode pumped solid state lasers has been derived.A method for calculating the output power in longitudinally diode pumped CW lasers has been proposed,which is represented as a function of the two parameters:the active medium length and transmissivity.The optimal design procedure has been found.Numerical calculations have shown a good consistency with our experimental result and the data in Refs. [3] and [4].
1998, 22(4): 207-211.
Abstract:
An optical detection technique for rapid measurement of surface roughness by using a laser beam is proposed.When a laser beam illuminate on the surface of a aluminum specimen,the space distribution of the reflected light intensity will be the function of the roughness of the surface of the specimen.And the intensity distribution can be measured with a plasma coupled device (PCD) and approximately expressed with Gaussian function.The broadness of the intensity distribution curve can be evaluated with standard deviation called Gaussian curve parameter (GCP).We find a experimental equation Ra=0.088GCP+0.032 to show the relationship between center line average roughness Ra and GCP in range of 0.1～0.5μm.
An optical detection technique for rapid measurement of surface roughness by using a laser beam is proposed.When a laser beam illuminate on the surface of a aluminum specimen,the space distribution of the reflected light intensity will be the function of the roughness of the surface of the specimen.And the intensity distribution can be measured with a plasma coupled device (PCD) and approximately expressed with Gaussian function.The broadness of the intensity distribution curve can be evaluated with standard deviation called Gaussian curve parameter (GCP).We find a experimental equation Ra=0.088GCP+0.032 to show the relationship between center line average roughness Ra and GCP in range of 0.1～0.5μm.
1998, 22(4): 211-214.
Abstract:
The following experiment phenomenon has been reported before:the power varying trend of o light and e light are opposite to each other with the laser cavity tuned,no matter what kind of Ne(Ne20 or the mixture of Ne20 and Ne22) is used and how much the mode split is.Now based on the theory of three level perturbation,the phenomenon is analyzed with the self consistent equations and the mutual gain saturation effect of "the single pair of modes" of the frequency splitting standing wave He-Ne lasers.
The following experiment phenomenon has been reported before:the power varying trend of o light and e light are opposite to each other with the laser cavity tuned,no matter what kind of Ne(Ne20 or the mixture of Ne20 and Ne22) is used and how much the mode split is.Now based on the theory of three level perturbation,the phenomenon is analyzed with the self consistent equations and the mutual gain saturation effect of "the single pair of modes" of the frequency splitting standing wave He-Ne lasers.
1998, 22(4): 215-217.
Abstract:
This paper introduces a multi points measurement of chain elements on line based on the simple point measurement,discusses about the edge flaw shape on chain element,and introduces in detail detection and control technique during production.Experiment shows that this measure improves the selecting rate of chain element on line.
This paper introduces a multi points measurement of chain elements on line based on the simple point measurement,discusses about the edge flaw shape on chain element,and introduces in detail detection and control technique during production.Experiment shows that this measure improves the selecting rate of chain element on line.
Thermal heat absorption of nonradiactive relaxation in active medium of high power solid state laser
1998, 22(4): 217-220.
Abstract:
In this paper,by analysing the characteristics of thermal heat absorption of active medium in high power solid state laser,we present the nonradiactive relaxation model of excited ions in active medium in continuous operation and give the dependence of thermal heat absorption caused by nonradiactive relaxation on laser oscillation.The influence of laser oscillation on diopters of laser rod is also given.Experimental results show accordance with theoretical model analysis.
In this paper,by analysing the characteristics of thermal heat absorption of active medium in high power solid state laser,we present the nonradiactive relaxation model of excited ions in active medium in continuous operation and give the dependence of thermal heat absorption caused by nonradiactive relaxation on laser oscillation.The influence of laser oscillation on diopters of laser rod is also given.Experimental results show accordance with theoretical model analysis.
1998, 22(4): 221-224.
Abstract:
The error model of classical Moire tomography is analyzed.The applicable range of current reconstruction method is limited through analyzing causes of the error.Reconstruction results of experimental temperature fields using classical Moire tomography are compared with real measured values to verify the error model.The key problem existing in conventional Moire tomography is analyzed and an method of wavefront retrieving based on phase unwrapping is presented.
The error model of classical Moire tomography is analyzed.The applicable range of current reconstruction method is limited through analyzing causes of the error.Reconstruction results of experimental temperature fields using classical Moire tomography are compared with real measured values to verify the error model.The key problem existing in conventional Moire tomography is analyzed and an method of wavefront retrieving based on phase unwrapping is presented.
1998, 22(4): 225-228.
Abstract:
This artical describes a new constant voltage and constant current gas laser switching power supply.The feature are using 20kHz switching circuit and thyristor circuit and giving up the heavy line transformer.Especially we use existing TV horizontal output transformer and normal IC to produce continuous adjustable light up voltage and constant working voltage for various He-Ne laser.It has superior ratio of quality versus price and easy made.
This artical describes a new constant voltage and constant current gas laser switching power supply.The feature are using 20kHz switching circuit and thyristor circuit and giving up the heavy line transformer.Especially we use existing TV horizontal output transformer and normal IC to produce continuous adjustable light up voltage and constant working voltage for various He-Ne laser.It has superior ratio of quality versus price and easy made.
1998, 22(4): 228-230.
Abstract:
This paper described a simulation training system,including optical collimator,CCD camera,bridge sensor and a microcomputer,for real time showing the welding process of a operator.With the system,we can give the proper judgment to the operation process.
This paper described a simulation training system,including optical collimator,CCD camera,bridge sensor and a microcomputer,for real time showing the welding process of a operator.With the system,we can give the proper judgment to the operation process.
1998, 22(4): 231-235.
Abstract:
In this paper,two dimensional temperature and internal stress distributions in a diode side pumped slab laser medium have been calculated by using finite difference method.The numerical calculation results have been analyzed,from which suitable cooling schemes for diode pumped slab lasers at different pumping level have been proposed.
In this paper,two dimensional temperature and internal stress distributions in a diode side pumped slab laser medium have been calculated by using finite difference method.The numerical calculation results have been analyzed,from which suitable cooling schemes for diode pumped slab lasers at different pumping level have been proposed.
1998, 22(4): 235-238.
Abstract:
The high power density,neodymium glass laser is used to laser shock process aluminum alloy 2024T62.Laser parameters:the duration(FWHM) is 30ns,the single laser pulse energy is 16.5 to 27.5J,the power density is 1.1 to 1.6GW/cm2.The test results show that the hardness of laser shocking zone is increased about 42%,the surface grains of laser shocking zone are fined and the fatigue life of aluminum alloy is increased significantly.With 95% confidence,the fatigue life of laser shock processing specimens is 5.4 to 14.5 times larger than the unprocessed specimens.
The high power density,neodymium glass laser is used to laser shock process aluminum alloy 2024T62.Laser parameters:the duration(FWHM) is 30ns,the single laser pulse energy is 16.5 to 27.5J,the power density is 1.1 to 1.6GW/cm2.The test results show that the hardness of laser shocking zone is increased about 42%,the surface grains of laser shocking zone are fined and the fatigue life of aluminum alloy is increased significantly.With 95% confidence,the fatigue life of laser shock processing specimens is 5.4 to 14.5 times larger than the unprocessed specimens.
1998, 22(4): 239-245.
Abstract:
The theory of CW UV Cu+ laser has been investigated,including the cathode fall theory for hollow cathode discharge,cathode sputtering effects,diffusion processes of the particles in the plasma and rate equations of the particles.The theoretical results have been verified.
The theory of CW UV Cu+ laser has been investigated,including the cathode fall theory for hollow cathode discharge,cathode sputtering effects,diffusion processes of the particles in the plasma and rate equations of the particles.The theoretical results have been verified.
1998, 22(4): 246-250.
Abstract:
The graphical analysis as well as numerical calculation has been used to study the effective reflectivity at antireflection coated facets of semiconductor lasers. Due to the wavelength dependence and finite spectral width of the reflection curve, the reflectivity which takes effect is generally higher than the minimum reflectivity claimed. Accounts have also been made on the choice of the wavelength, where the reflectivity is minimized,in order to increase the effectiveness of the antireflection coatings.
The graphical analysis as well as numerical calculation has been used to study the effective reflectivity at antireflection coated facets of semiconductor lasers. Due to the wavelength dependence and finite spectral width of the reflection curve, the reflectivity which takes effect is generally higher than the minimum reflectivity claimed. Accounts have also been made on the choice of the wavelength, where the reflectivity is minimized,in order to increase the effectiveness of the antireflection coatings.
1998, 22(4): 250-253.
Abstract:
In this paper,the principle and basic design of laser diode's temperature control were described.With the PID circuit,the surround temperature accuracy could be controlled within ±0.5℃。The threshold current decreased and the output power increased apparently with good linear.
In this paper,the principle and basic design of laser diode's temperature control were described.With the PID circuit,the surround temperature accuracy could be controlled within ±0.5℃。The threshold current decreased and the output power increased apparently with good linear.
1998, 22(4): 253-255.
Abstract:
In this paper the course of strokes distortion in laser raster scaning engraving is analysed in detail and a method based on the responding of laser power supply is presented.
In this paper the course of strokes distortion in laser raster scaning engraving is analysed in detail and a method based on the responding of laser power supply is presented.
1998, 22(4): 256-260.
Abstract:
We report the spectroscopic study and nonlinear optical properties for a series of novel mixed ligand [Ru(bpy)2L]2+ complexes.Herebpy=2,2-bipyridine,Lisimidazo[f]1,10 phenanthroline(IP)-2-phenylimidazo1,10-phenanthroline(PIP) and the derivatives and their complexes [Ru(bpy)2L]2+.The effects of different electron donor and acceptor groups on the absorption and emission spectra are studied with nanosecond resolution.Time resolved luminescence studies reveal that the addition of calf thymus DNA into the complex solution results in increases both the emissive intensities and excited state lifetimes and indicates that the electron group on L has no significant effect on the intercalation binding mode between DNA and the complexes.The nonlinear optical of ruthenium complexes with good charge transfer properties were studied by degenerate four wave mixing(DFWM) at 450nm.The third order nonlinear optical susceptibilities and the third order hyperpolarizabilities of molecules,and the in fluence on the nonlineal optical coefficents of compounds were discussed.
We report the spectroscopic study and nonlinear optical properties for a series of novel mixed ligand [Ru(bpy)2L]2+ complexes.Herebpy=2,2-bipyridine,Lisimidazo[f]1,10 phenanthroline(IP)-2-phenylimidazo1,10-phenanthroline(PIP) and the derivatives and their complexes [Ru(bpy)2L]2+.The effects of different electron donor and acceptor groups on the absorption and emission spectra are studied with nanosecond resolution.Time resolved luminescence studies reveal that the addition of calf thymus DNA into the complex solution results in increases both the emissive intensities and excited state lifetimes and indicates that the electron group on L has no significant effect on the intercalation binding mode between DNA and the complexes.The nonlinear optical of ruthenium complexes with good charge transfer properties were studied by degenerate four wave mixing(DFWM) at 450nm.The third order nonlinear optical susceptibilities and the third order hyperpolarizabilities of molecules,and the in fluence on the nonlineal optical coefficents of compounds were discussed.
