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RSS2003 Vol. 27, No. 5
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2003, 27(5): 385-389.
[Abstract]
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Abstract:
A novel packet switching adopting in-band multi-wavelength optical label is introduced,in which optical header is labeled by several optical pulses at different wavelengths in the same optical communication channel band as optical payload.The switching fundamental and its implementation techniques,including optical transmitter with header generation and packet formation,receiver with data restoration and switching node with route processing,are described.A simplified experiment demonstrated the switching principle.
A novel packet switching adopting in-band multi-wavelength optical label is introduced,in which optical header is labeled by several optical pulses at different wavelengths in the same optical communication channel band as optical payload.The switching fundamental and its implementation techniques,including optical transmitter with header generation and packet formation,receiver with data restoration and switching node with route processing,are described.A simplified experiment demonstrated the switching principle.
2003, 27(5): 390-392,395.
Abstract:
A novel electro optical hybrid current transducer is designed.It consists of four parts:a sensor head,an optical fiber transmitter and optoelectric converter,a signal processing circuit and a power supply.In the operation environment,this device has the advantages of high insulation,high reliability,small mass and high inference rejection.Measurement errors are analyzed in this paper.
A novel electro optical hybrid current transducer is designed.It consists of four parts:a sensor head,an optical fiber transmitter and optoelectric converter,a signal processing circuit and a power supply.In the operation environment,this device has the advantages of high insulation,high reliability,small mass and high inference rejection.Measurement errors are analyzed in this paper.
2003, 27(5): 393-395.
Abstract:
In a new OADM (optical add/drop multiplex) architecture for packet service is described. It uses the auto correlation and cross correlation of optical orthogonal codes for address recognition by all optical method. The principle is put into the optical network element. The design method is described and discussed. The application demonstration and simulation are given.
In a new OADM (optical add/drop multiplex) architecture for packet service is described. It uses the auto correlation and cross correlation of optical orthogonal codes for address recognition by all optical method. The principle is put into the optical network element. The design method is described and discussed. The application demonstration and simulation are given.
2003, 27(5): 396-397,399.
Abstract:
In order to improve the surface performance of A3 steel,we utilize a high power CO2 laser beam to treat TiC-B4C-SiC-Co clad surface. It is obvious that the laser beam scanning speed is a important factor on the structure,hardness and resistance to abrasion of the alloy surface. This paper introduces the experimental research procedure,and the experimental results,which are useful to select the beam scanning and other technical parameters.
In order to improve the surface performance of A3 steel,we utilize a high power CO2 laser beam to treat TiC-B4C-SiC-Co clad surface. It is obvious that the laser beam scanning speed is a important factor on the structure,hardness and resistance to abrasion of the alloy surface. This paper introduces the experimental research procedure,and the experimental results,which are useful to select the beam scanning and other technical parameters.
2003, 27(5): 398-399.
Abstract:
In the laser application,sometimes it is needed that laser beams of different wavelengths act on the research object at the same time. The integration of laser beams is usually operated manually,and observed and defined by eyes,so that dependability is difficult to be guaranteed. Integration of laser beams under the computer control is to gather each bunch of laser beam signals to the computer and control the reflector to adjust the direction of laser beams.With such a system,the multi laser beams can be integrated effectirely in the practical application.
In the laser application,sometimes it is needed that laser beams of different wavelengths act on the research object at the same time. The integration of laser beams is usually operated manually,and observed and defined by eyes,so that dependability is difficult to be guaranteed. Integration of laser beams under the computer control is to gather each bunch of laser beam signals to the computer and control the reflector to adjust the direction of laser beams.With such a system,the multi laser beams can be integrated effectirely in the practical application.
2003, 27(5): 400-402,406.
Abstract:
The principles of phacoemulsification on the cataract extraction surgery are presented briefly. Developments on laserphaco are introduced.A few kinds of lasers and their applications are compared.
The principles of phacoemulsification on the cataract extraction surgery are presented briefly. Developments on laserphaco are introduced.A few kinds of lasers and their applications are compared.
2003, 27(5): 403-406.
Abstract:
Based on the beam coherence-polarization (BCP) matrix and the propagation law,the expressions for the degree of polarization and intensity distribution of nonuniformly polarized (NUP) beams through an aperture are derived. Numerical examples for a type of uniform intensity distribution NUP beams are given. It is shown that remarkable changes in both polarization and intensity distributions take place after the aperture. There are oscillations of the degree of polarization at the transversal plane and the intensity profile is nonuniform. However,the polarization becomes uniform in the far field.
Based on the beam coherence-polarization (BCP) matrix and the propagation law,the expressions for the degree of polarization and intensity distribution of nonuniformly polarized (NUP) beams through an aperture are derived. Numerical examples for a type of uniform intensity distribution NUP beams are given. It is shown that remarkable changes in both polarization and intensity distributions take place after the aperture. There are oscillations of the degree of polarization at the transversal plane and the intensity profile is nonuniform. However,the polarization becomes uniform in the far field.
2003, 27(5): 407-408.
Abstract:
Based on the theory of Michelson's interferometer,a new method is used to measure the index of crystals.The theoretical formula is obtained under the condition that the rotating angle is small.Combined with CCD and microprocessor,the measurement precision is improved a lot.
Based on the theory of Michelson's interferometer,a new method is used to measure the index of crystals.The theoretical formula is obtained under the condition that the rotating angle is small.Combined with CCD and microprocessor,the measurement precision is improved a lot.
2003, 27(5): 409-410,414.
Abstract:
In order to optimize the design of fiber Raman laser,a fiber laser with DCF as gain medium under a simplified model and its output characters are analyzed.Some methods are put forward to optimize the design of fiber lasers.Laser output can be optimized with alterations of fiber length and output coupling coefficient,and the output power can be changed with alteration of pump power.Applying the model to the multi wavelength lasers,four-wavelength lasers have been obtained.
In order to optimize the design of fiber Raman laser,a fiber laser with DCF as gain medium under a simplified model and its output characters are analyzed.Some methods are put forward to optimize the design of fiber lasers.Laser output can be optimized with alterations of fiber length and output coupling coefficient,and the output power can be changed with alteration of pump power.Applying the model to the multi wavelength lasers,four-wavelength lasers have been obtained.
2003, 27(5): 411-414.
Abstract:
The guided to leaky mode conversion with the induced diffraction grating from the collinear surface acoustic wave (SAW) possess potential application in onboard optical demultiplexing of optic communication systems. This phenomenon is analyzed using the coupled mode theory. Mode conversion efficiency has been calculated as functions of acoustic frequency,interaction length,guiding layer thickness,and acoustic drive power density. It is shown that the x-cut configuration features the highest mode conversion efficiency,measured mode conversion efficiency as high as 90% is obtained at the relevant acoustic drive power density and interaction length.
The guided to leaky mode conversion with the induced diffraction grating from the collinear surface acoustic wave (SAW) possess potential application in onboard optical demultiplexing of optic communication systems. This phenomenon is analyzed using the coupled mode theory. Mode conversion efficiency has been calculated as functions of acoustic frequency,interaction length,guiding layer thickness,and acoustic drive power density. It is shown that the x-cut configuration features the highest mode conversion efficiency,measured mode conversion efficiency as high as 90% is obtained at the relevant acoustic drive power density and interaction length.
2003, 27(5): 415-418.
Abstract:
Based on the optical fiber loss,solving the modified nonlinear Schrodinger equations,the paper analyses the function affected by GVD and SPM in single-mode optical fiber in negative GVD area. It quantitatively calculates soliton effect picosecond pulse compression induced by optical fiber loss and initial orthochirp. The result shows that initial orthochirp improves the bad affect of compression factors due to the loss and stops the increase of the best optical fiber length. If an appropriate optical fiber length and initial peak power is selected,efficient compression of orthochirp pulse can be attained in single-mode optical fiber.
Based on the optical fiber loss,solving the modified nonlinear Schrodinger equations,the paper analyses the function affected by GVD and SPM in single-mode optical fiber in negative GVD area. It quantitatively calculates soliton effect picosecond pulse compression induced by optical fiber loss and initial orthochirp. The result shows that initial orthochirp improves the bad affect of compression factors due to the loss and stops the increase of the best optical fiber length. If an appropriate optical fiber length and initial peak power is selected,efficient compression of orthochirp pulse can be attained in single-mode optical fiber.
2003, 27(5): 419-422.
Abstract:
This paper presents the principle and measuring method of a laser instrument used to measure runway horizontal visibility and approach visibility. By means of the co operation target,the instrument could simply measure approach visibility,greatly increase amplitude of receiving signal and improve its sensitivity.PIN photodiode can be used as photoelectrical transformation unit to detect the amplitude of receiving signal. By means of transmission ruler,curves of relative errors are optimized. Measurement precision of visibility,especially lower visibility is improved.Measurement error of runway horizontal visibility and approach visibility is less than 12%.
This paper presents the principle and measuring method of a laser instrument used to measure runway horizontal visibility and approach visibility. By means of the co operation target,the instrument could simply measure approach visibility,greatly increase amplitude of receiving signal and improve its sensitivity.PIN photodiode can be used as photoelectrical transformation unit to detect the amplitude of receiving signal. By means of transmission ruler,curves of relative errors are optimized. Measurement precision of visibility,especially lower visibility is improved.Measurement error of runway horizontal visibility and approach visibility is less than 12%.
2003, 27(5): 423-427.
Abstract:
The general situation of research and development of the technology of laser radiation protection and optoelectronic countermeasures are introduced. The following aspects are included: conventional protective devices for laser,new techniques and materials for protection against laser radiation,laser protection in the photoelectric sensors and the optical windows of weapon equipment,synthesis protection systems against laser radiation,assessment and test for laser protection devices,protective means against laser radiation. Finally,the developing trend of techniques of laser radiation protection is described.
The general situation of research and development of the technology of laser radiation protection and optoelectronic countermeasures are introduced. The following aspects are included: conventional protective devices for laser,new techniques and materials for protection against laser radiation,laser protection in the photoelectric sensors and the optical windows of weapon equipment,synthesis protection systems against laser radiation,assessment and test for laser protection devices,protective means against laser radiation. Finally,the developing trend of techniques of laser radiation protection is described.
2003, 27(5): 428-430.
Abstract:
A research detail of Nd:YAG 1.319μm extracavity-doubling using LBO crystal is reported.LBO crystal is adopted by type-Ⅰ noncritical phase-matched(NCPM)and temperature tuned.The experiment shows that using LBO type-Ⅰnoncritical phase-match is effective to get a higher SHG efficiency.With a 1300mJ incident pump laser while temperature is 8.4℃,855mJ 660nm TEM00 mode red laser is obtained,the conversion efficiency is up to 66% and the power instability of output laser is less than ±3%.
A research detail of Nd:YAG 1.319μm extracavity-doubling using LBO crystal is reported.LBO crystal is adopted by type-Ⅰ noncritical phase-matched(NCPM)and temperature tuned.The experiment shows that using LBO type-Ⅰnoncritical phase-match is effective to get a higher SHG efficiency.With a 1300mJ incident pump laser while temperature is 8.4℃,855mJ 660nm TEM00 mode red laser is obtained,the conversion efficiency is up to 66% and the power instability of output laser is less than ±3%.
2003, 27(5): 431-433.
Abstract:
Three-dimensional beam propagation method based on the series expansion method(3D-SEM-BPM) transform the BPM into the first-order normal differential equations. The method has the merits of simple calculation and high calculation efficiency. The lithium niobate electro optic waveguide modulator with Mach-Zehnder structure is simulated with this method. We got its optical field distribution and acquired its optimal structure and its power loss curve. The function of tangent is applied to map the infinite space into a finite space to avoid boundary truncation.
Three-dimensional beam propagation method based on the series expansion method(3D-SEM-BPM) transform the BPM into the first-order normal differential equations. The method has the merits of simple calculation and high calculation efficiency. The lithium niobate electro optic waveguide modulator with Mach-Zehnder structure is simulated with this method. We got its optical field distribution and acquired its optimal structure and its power loss curve. The function of tangent is applied to map the infinite space into a finite space to avoid boundary truncation.
2003, 27(5): 434-436.
Abstract:
The ceramic layers were cladded on W6Mo5Cr4V2 high speed steel surface with a 2kW CO2 laser,and the net of three dimension ceramic layers are formed.The steel was quenched and tempered The test results indicate that the high strength and toughness of the steel combines with their properties of the ceramic layers forming a well distribution. The highesthardness of the layers can reach 1887HV,and the wear resistances are increased (3～7) times compared to those of the steel in common heat treatment. The high temperature hardness and temper stability are enhanced,too.
The ceramic layers were cladded on W6Mo5Cr4V2 high speed steel surface with a 2kW CO2 laser,and the net of three dimension ceramic layers are formed.The steel was quenched and tempered The test results indicate that the high strength and toughness of the steel combines with their properties of the ceramic layers forming a well distribution. The highesthardness of the layers can reach 1887HV,and the wear resistances are increased (3～7) times compared to those of the steel in common heat treatment. The high temperature hardness and temper stability are enhanced,too.
2003, 27(5): 437-439.
Abstract:
The refractive index profile of gradient-index (GRIN) lens obeys square rule,as same as multimode-fiber. Based on this fact,the research and design of micro-align-lens which is fabricated by means of multimode-fiber fabrication techniques is carried out. Results show that the micro-align-lens has good performance as single-mode-fiber(SMF) collimator.Compared with GRIN lens,ithas smaller size and can be fabricated simply.
The refractive index profile of gradient-index (GRIN) lens obeys square rule,as same as multimode-fiber. Based on this fact,the research and design of micro-align-lens which is fabricated by means of multimode-fiber fabrication techniques is carried out. Results show that the micro-align-lens has good performance as single-mode-fiber(SMF) collimator.Compared with GRIN lens,ithas smaller size and can be fabricated simply.
2003, 27(5): 440-442.
Abstract:
The basic principle expand beam fiber connector is firstly introduced. Then its loss mechanism is analyzed,including the variable loss and the invariable loss. The variable loss comes from the error of leveling for cells of the system,such as the loss of radial excursion,the loss of portrait excursion and the loss portrait obliquity. In all loss,the radial excursion is the greatest,then the loss of portrait obliquity,the invariable loss and the loss of portrait excursion. The invariable loss comes from the materials and surface processing of the system itself,such as the loss of Fresnel,ball aberration,diffraction,chromatic aberration and absorb.Finally,the efficient methods to reduce loss are presented.
The basic principle expand beam fiber connector is firstly introduced. Then its loss mechanism is analyzed,including the variable loss and the invariable loss. The variable loss comes from the error of leveling for cells of the system,such as the loss of radial excursion,the loss of portrait excursion and the loss portrait obliquity. In all loss,the radial excursion is the greatest,then the loss of portrait obliquity,the invariable loss and the loss of portrait excursion. The invariable loss comes from the materials and surface processing of the system itself,such as the loss of Fresnel,ball aberration,diffraction,chromatic aberration and absorb.Finally,the efficient methods to reduce loss are presented.
2003, 27(5): 443-446.
Abstract:
Thin film materials have been widely used in micro electronics,superconductor,and bioceramics materials. In order to obtain high quality thin films,deposition have attracted more attention. In this paper the principle,the characteristics of the pulsed laser deposition technique are introduced. Its applications in semiconductor,high temperature superconductor,diamondlike,ferroelectric and bioceramics thin films and its current research status are reviewed. The future application trend is prospected.
Thin film materials have been widely used in micro electronics,superconductor,and bioceramics materials. In order to obtain high quality thin films,deposition have attracted more attention. In this paper the principle,the characteristics of the pulsed laser deposition technique are introduced. Its applications in semiconductor,high temperature superconductor,diamondlike,ferroelectric and bioceramics thin films and its current research status are reviewed. The future application trend is prospected.
2003, 27(5): 447-449,452.
Abstract:
A recurrence propagation formula of Hermit-Gaussian(H-G) beams through a paraxial optical ABCD system with an internal hard edge aperture is derived,from which the analytical propagation equation of H-G beams of any orders can be obtained,and the effect of the aperture on the propagation can studied analytically. Numerical examples are put forward to illustrate the application and advantage of our analytical results.
A recurrence propagation formula of Hermit-Gaussian(H-G) beams through a paraxial optical ABCD system with an internal hard edge aperture is derived,from which the analytical propagation equation of H-G beams of any orders can be obtained,and the effect of the aperture on the propagation can studied analytically. Numerical examples are put forward to illustrate the application and advantage of our analytical results.
2003, 27(5): 450-452.
Abstract:
Based on optical transmission matrix,multi-element thermal lens resonator is analyzed. The way to adjust rods' matching and coupling is presnted. Theoretical analysis is accordant with the experiment results. For three rod serial CW Nd3+:YAG laser,the stable output power between (0～1)kW is acquired.
Based on optical transmission matrix,multi-element thermal lens resonator is analyzed. The way to adjust rods' matching and coupling is presnted. Theoretical analysis is accordant with the experiment results. For three rod serial CW Nd3+:YAG laser,the stable output power between (0～1)kW is acquired.
2003, 27(5): 453-456,459.
Abstract:
The processes of pulsed laser deposition(PLD) technology,one of the most attractive thin film preparation methods,are described. The properties are listed in contrast with other methods. The fundamental approaches and the latest appropriate developments in PLD with ultra-fast pulsed laser,pulsed-laser-arc,and dual-beam lasers are discussed in detail.
The processes of pulsed laser deposition(PLD) technology,one of the most attractive thin film preparation methods,are described. The properties are listed in contrast with other methods. The fundamental approaches and the latest appropriate developments in PLD with ultra-fast pulsed laser,pulsed-laser-arc,and dual-beam lasers are discussed in detail.
2003, 27(5): 457-459.
Abstract:
The surface reflectivity of Kevlar/epoxy doesn't change when there are no chemical and physical changes of the composite reinforcced by polyaryl amide fibers irradiated by laser beam.However it will change.The ablation threshold of the material can be obtained by monitoring its surface reflectivity changes using integrated spheres and photodiode system.This method can trace the increase of the laser power to get the ablation threshold of the material.This paper has proved the feasibility of this method by measuring the threshold of the composite reinforced by polyaryl amide fibers irradiated by laser beam with a wavelength of 1.06μm.
The surface reflectivity of Kevlar/epoxy doesn't change when there are no chemical and physical changes of the composite reinforcced by polyaryl amide fibers irradiated by laser beam.However it will change.The ablation threshold of the material can be obtained by monitoring its surface reflectivity changes using integrated spheres and photodiode system.This method can trace the increase of the laser power to get the ablation threshold of the material.This paper has proved the feasibility of this method by measuring the threshold of the composite reinforced by polyaryl amide fibers irradiated by laser beam with a wavelength of 1.06μm.
2003, 27(5): 460-462,465.
Abstract:
Experimental study of laser milling were carried out on the surface of silicon wafer with different YAG lasers and laser processing parameters. The effect of laser processing parameters on the milling surface quality were studied systematically. Different shapes and structures were fabricated on the surface with the optimized procedures.
Experimental study of laser milling were carried out on the surface of silicon wafer with different YAG lasers and laser processing parameters. The effect of laser processing parameters on the milling surface quality were studied systematically. Different shapes and structures were fabricated on the surface with the optimized procedures.
2003, 27(5): 463-465.
Abstract:
The laser beam classification,a very interesting subject in laser optics,is reviewed and analyzed. Based on the second order moment method and Wigner distribution function,and in accordance with their spatial symmetry,laser beams can be classified as three types,i.e. stigmatic (ST) beams,simple astigmatic (SA) beams and general astigmatic (GA) beams. On the other hand,according to their spatial coherence,there are two types of laser beams,namely,partially coherent beams and fully coherent beams. The independent characteristic parameters of different types of laser beams and their relation are analyzed.
The laser beam classification,a very interesting subject in laser optics,is reviewed and analyzed. Based on the second order moment method and Wigner distribution function,and in accordance with their spatial symmetry,laser beams can be classified as three types,i.e. stigmatic (ST) beams,simple astigmatic (SA) beams and general astigmatic (GA) beams. On the other hand,according to their spatial coherence,there are two types of laser beams,namely,partially coherent beams and fully coherent beams. The independent characteristic parameters of different types of laser beams and their relation are analyzed.
2003, 27(5): 466-469.
Abstract:
A 15kW switching power supply with the function of constant voltage current limit for YAG pulse laser is presented. In this paper,the operation principle of the control circuit is discussed,and the implemented circuit is also described. Analytical and experimental results prove that the power supply has good static characteristics,fast dynamic response and high reliability. Furthermore,the configuration is simple and the cost is low.
A 15kW switching power supply with the function of constant voltage current limit for YAG pulse laser is presented. In this paper,the operation principle of the control circuit is discussed,and the implemented circuit is also described. Analytical and experimental results prove that the power supply has good static characteristics,fast dynamic response and high reliability. Furthermore,the configuration is simple and the cost is low.
2003, 27(5): 470-472.
Abstract:
This article makes a research in theory and experiment on the changes of the interference signal and the laser intensity of an interferometer with optical feedback in a He-Ne laser.When the main feedback mirror moves,the curve of the laser output intensity is a sine wave but the interference signal is a curve with two peaks in a period.One peak is higher than the other one.When the feedback mirror changes its moving direction,the order that the two peaks come out will change too.The article analyses the experimental results in theory and simulates the interference signal and the laser intensity signal.The simulation results are in good agreement with the experiment results.A measuring method is discussed which can judge the moving direction of the moving object easily and this method is easy to be realized.
This article makes a research in theory and experiment on the changes of the interference signal and the laser intensity of an interferometer with optical feedback in a He-Ne laser.When the main feedback mirror moves,the curve of the laser output intensity is a sine wave but the interference signal is a curve with two peaks in a period.One peak is higher than the other one.When the feedback mirror changes its moving direction,the order that the two peaks come out will change too.The article analyses the experimental results in theory and simulates the interference signal and the laser intensity signal.The simulation results are in good agreement with the experiment results.A measuring method is discussed which can judge the moving direction of the moving object easily and this method is easy to be realized.
2003, 27(5): 473-476.
Abstract:
The vector diffraction characteristic must be considered to diffractive optical elements whose features are on the order of or smaller than the wavelength of the incident illumination. We present the rigorous vector analysis of diffractive micro cylindrical lenses that are finite in extent using a two-dimension finite-difference time-domain (FDTD) method. Using these effective analysis tools,lens' characteristics of focal depth and focal shifthave been analyzed rigorously. The results are compared with the scalar theory and the effects of quantified profiles are presented,respectively. Minimizing the numerical dispersion in the FDTD calculation region,setting the absorbing boundary and calculating the steady state electromagnetic fields' propagation from the FDTD region to the observation plane has been discussed in detail.
The vector diffraction characteristic must be considered to diffractive optical elements whose features are on the order of or smaller than the wavelength of the incident illumination. We present the rigorous vector analysis of diffractive micro cylindrical lenses that are finite in extent using a two-dimension finite-difference time-domain (FDTD) method. Using these effective analysis tools,lens' characteristics of focal depth and focal shifthave been analyzed rigorously. The results are compared with the scalar theory and the effects of quantified profiles are presented,respectively. Minimizing the numerical dispersion in the FDTD calculation region,setting the absorbing boundary and calculating the steady state electromagnetic fields' propagation from the FDTD region to the observation plane has been discussed in detail.
2003, 27(5): 477-479,483.
Abstract:
The fluorescence spectra of alcohol solution induced by ultraviolet light and its characteristic are studied experimentally and theoretically in this paper. The results show that alcohol solution can emit strong fluorescence at 395nm when excited by ultraviolet light with the wavelength of 254nm.It is considered that this fluorescence comes from the transition from n→σ* of the lone-pair electrons in the hetero atom group (C-OH) of the ethanol molecule. Investigation on the fluorescence spectra and its characteristics will contribute to study of other organic macromolecule fluorescence spectra when alcohol serves as solute.
The fluorescence spectra of alcohol solution induced by ultraviolet light and its characteristic are studied experimentally and theoretically in this paper. The results show that alcohol solution can emit strong fluorescence at 395nm when excited by ultraviolet light with the wavelength of 254nm.It is considered that this fluorescence comes from the transition from n→σ* of the lone-pair electrons in the hetero atom group (C-OH) of the ethanol molecule. Investigation on the fluorescence spectra and its characteristics will contribute to study of other organic macromolecule fluorescence spectra when alcohol serves as solute.
2003, 27(5): 480-483.
Abstract:
In this paper,finite-elements method is used to simulate the film thickness uniformity at different rotation and different time. The result shows that the uniformity of film thickness can be improved if the rotation and time are selected properly.
In this paper,finite-elements method is used to simulate the film thickness uniformity at different rotation and different time. The result shows that the uniformity of film thickness can be improved if the rotation and time are selected properly.
2003, 27(5): 484-485,489.
Abstract:
The frequency stability of CW CO2 laser was measured with beat frequency method.A computer received data directly from a counter through IEEE488 interface,then calculated the laser's frequency stability.A pulsed CO2 laser's frequency stability was measured with pulse beterodyne method.
The frequency stability of CW CO2 laser was measured with beat frequency method.A computer received data directly from a counter through IEEE488 interface,then calculated the laser's frequency stability.A pulsed CO2 laser's frequency stability was measured with pulse beterodyne method.
2003, 27(5): 486-489.
Abstract:
This paper introduces several methods of laser welding combined with other heat resources,and investigates why they decrease or eliminate the drawbacks of laser welding while embodying its advantages. We can draw a conclusion that laser welding combined with other heat resources is a trend of laser welding development.
This paper introduces several methods of laser welding combined with other heat resources,and investigates why they decrease or eliminate the drawbacks of laser welding while embodying its advantages. We can draw a conclusion that laser welding combined with other heat resources is a trend of laser welding development.
2003, 27(5): 490-492.
Abstract:
Based on the expansion of the window function of a hard edge aperture into a finite sum of complex Gaussian functions,the recurrence propagation equation of cosh Gaussian(ChG)beams through a multi apertured paraxial ABCD optical system is derived,which permits us to study the propagation of ChG beams through hard edge optics analytically.Numerical results are given and compared with those derived by the straightforward integral of the Collins formula,which shows the advantage of saving the computer time greatly by means of our analytical formula.
Based on the expansion of the window function of a hard edge aperture into a finite sum of complex Gaussian functions,the recurrence propagation equation of cosh Gaussian(ChG)beams through a multi apertured paraxial ABCD optical system is derived,which permits us to study the propagation of ChG beams through hard edge optics analytically.Numerical results are given and compared with those derived by the straightforward integral of the Collins formula,which shows the advantage of saving the computer time greatly by means of our analytical formula.
2003, 27(5): 493-496.
Abstract:
Aiming at the exist problem of saw blade made in Laiwu Steel and Iron Co.saw blade treated by laser was studied in the paper.The result proved that the hardness and anti-abrasion of the saw teeth are increased,the vibration and stability of the saw blade were improved which were heat-treated by laser,so the longevity of saw and quality of sawing can be ensured easily.
Aiming at the exist problem of saw blade made in Laiwu Steel and Iron Co.saw blade treated by laser was studied in the paper.The result proved that the hardness and anti-abrasion of the saw teeth are increased,the vibration and stability of the saw blade were improved which were heat-treated by laser,so the longevity of saw and quality of sawing can be ensured easily.
