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RSS2005 Vol. 29, No. 1
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2005, 29(1): 1-4,13.
[Abstract]
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Abstract:
This article reviews and analyzes the restructuring of missile defense programs and its impact,particularly the future development of the airborne laser weapons.
This article reviews and analyzes the restructuring of missile defense programs and its impact,particularly the future development of the airborne laser weapons.
2005, 29(1): 5-8.
Abstract:
According to intracavity double frequency crystal customarily working-state analysis,KTP crystal under non-central-axis radiation interior precise temperature field is first obtained by analytical analysis method,and relevant parameters,affecting crystal interior temperature field are analyzed.This research will be theoretically established for effectively resolve thermal effect problem in the laser system.
According to intracavity double frequency crystal customarily working-state analysis,KTP crystal under non-central-axis radiation interior precise temperature field is first obtained by analytical analysis method,and relevant parameters,affecting crystal interior temperature field are analyzed.This research will be theoretically established for effectively resolve thermal effect problem in the laser system.
2005, 29(1): 9-10,17.
Abstract:
In order to overcome the shortcoming of long time interval between two shoots in the high-energy laser by using phase change material(PCM) cooled mirror,a novel semiconductor-cooled composite phase chang silicon mirror is presented in this paper.Thermal process of laser radiation of solid silicon mirror,PCM and semiconductor-cooled mirror is simulated by ANSYS finite element program. From the largest temperature-time curves there can be seen that semiconductor-cooled composite phase chang silicon mirror can restore the temperature of mirror and elastic deformation to their start for 5s in the 25W of refrigerating output under 20℃ of environment temperature and 100W of net absorption heat quantity.
In order to overcome the shortcoming of long time interval between two shoots in the high-energy laser by using phase change material(PCM) cooled mirror,a novel semiconductor-cooled composite phase chang silicon mirror is presented in this paper.Thermal process of laser radiation of solid silicon mirror,PCM and semiconductor-cooled mirror is simulated by ANSYS finite element program. From the largest temperature-time curves there can be seen that semiconductor-cooled composite phase chang silicon mirror can restore the temperature of mirror and elastic deformation to their start for 5s in the 25W of refrigerating output under 20℃ of environment temperature and 100W of net absorption heat quantity.
2005, 29(1): 11-13.
Abstract:
Characteristics of Cu-Al powder alloys of reaction laser sintering are investigated by study on variation process of sintering temperature,transformation of product phase,densification behavior and hardness of samples.It is showed that under laser power 800W and irradiation time 16s,reaction of sample penetrates deeply,characterization of serious and rapid propagating sintering appers,and phases were formed within short time of reaction stage during laser heating.All of the samples shrinks,and metastable martensite(M) Cu3Al is formed in Cu75Al25 alloy.
Characteristics of Cu-Al powder alloys of reaction laser sintering are investigated by study on variation process of sintering temperature,transformation of product phase,densification behavior and hardness of samples.It is showed that under laser power 800W and irradiation time 16s,reaction of sample penetrates deeply,characterization of serious and rapid propagating sintering appers,and phases were formed within short time of reaction stage during laser heating.All of the samples shrinks,and metastable martensite(M) Cu3Al is formed in Cu75Al25 alloy.
2005, 29(1): 14-17.
Abstract:
The dynamic model for a new all-optical wavelength converter (AOWC) using single-port-coupled semiconductor optical amplifier (SOA) based on cross gain modulation (XGM) is presented.Based on the dynamic model,factors which affect output extinction ratio,such as signal power,probe power,rear facet reflectivity,converted wavelength span,biased current,are analyzed respectively.The numerical result shows such a converter do have better extinction ratio character than a traditional AOWC.
The dynamic model for a new all-optical wavelength converter (AOWC) using single-port-coupled semiconductor optical amplifier (SOA) based on cross gain modulation (XGM) is presented.Based on the dynamic model,factors which affect output extinction ratio,such as signal power,probe power,rear facet reflectivity,converted wavelength span,biased current,are analyzed respectively.The numerical result shows such a converter do have better extinction ratio character than a traditional AOWC.
2005, 29(1): 18-20.
Abstract:
A general discussion on tunable semiconductor lasers for high speed optical communication is presented,with emphasis on SSG-DBR lasers.Then a novel temperature feedback control scheme for frequency stabilization is described. Using bias current control,absolute wavelength stabilization within 1nm has been achieved with SMSR better than 35dB in the temperature range of 20℃~70℃.This simple,effective stabilization method will play an important role in obtaining highly reliable light sources for optical network.
A general discussion on tunable semiconductor lasers for high speed optical communication is presented,with emphasis on SSG-DBR lasers.Then a novel temperature feedback control scheme for frequency stabilization is described. Using bias current control,absolute wavelength stabilization within 1nm has been achieved with SMSR better than 35dB in the temperature range of 20℃~70℃.This simple,effective stabilization method will play an important role in obtaining highly reliable light sources for optical network.
2005, 29(1): 21-23.
Abstract:
In the all-metal radio frequency excited CO2 laser,the temperature distribution in the discharge region varies with the gas mixture,input power and the background temperature.Besides the above factors,the thickness of the metal crust and the insulated gas width between the crust and metal electrode will also affect the temperature distribution to some extent.The temperature distribution in the discharge region is analyzed,which provides a good reference of designing the laser structure and selecting the gas mixture.
In the all-metal radio frequency excited CO2 laser,the temperature distribution in the discharge region varies with the gas mixture,input power and the background temperature.Besides the above factors,the thickness of the metal crust and the insulated gas width between the crust and metal electrode will also affect the temperature distribution to some extent.The temperature distribution in the discharge region is analyzed,which provides a good reference of designing the laser structure and selecting the gas mixture.
2005, 29(1): 24-27.
Abstract:
By means of Monte Carlo simulation of the process that photon transferring in the water,the depolarization of the polarized laser beam in the ocean is studied,as well as the effect of different ocean optical properties.The depolarization of different sea depth is obtained.The result shows that seawater with lots of particles playes great part in the depolarization of the polarized laser beam.When the polarized laser transmittes some distance under seawater,it will turn into depolarized laser.The particles with difference size distributed in the seawater are the main reason of the depolarization of seawater.The ocean optical property has great effect on the depolarization of seawater.As the increasing of the ocean attenuation coefficient,the transferring distance at which polarized laser turnes into depolarized laser is decreasing.
By means of Monte Carlo simulation of the process that photon transferring in the water,the depolarization of the polarized laser beam in the ocean is studied,as well as the effect of different ocean optical properties.The depolarization of different sea depth is obtained.The result shows that seawater with lots of particles playes great part in the depolarization of the polarized laser beam.When the polarized laser transmittes some distance under seawater,it will turn into depolarized laser.The particles with difference size distributed in the seawater are the main reason of the depolarization of seawater.The ocean optical property has great effect on the depolarization of seawater.As the increasing of the ocean attenuation coefficient,the transferring distance at which polarized laser turnes into depolarized laser is decreasing.
2005, 29(1): 28-31,34.
Abstract:
Laser conducting-limited welding of thin-wall HR-2 hydrogen-resistant stainless steel (HRSS) parts is discussed,processing parameters is studied,fluctuation of penetration and its influencing factors are analyzed,and measures to control fluctuation of penetration are presented.It is found that the maximal depth of fusion can be exceeded,and the fluctuation of penetration can be lessened,by taking measures such as low welding speed and preheating,when the HR-2 HRSS is welded by CO2 laser beam conduction-limited welding.With appropriate processing parameters and measures during laser conducting-limited welding of thin-wall HR-2 HRSS parts,depth of fusion can exceed 0.25mm,its fluctuation can be controlled in scope of ±10%,and good quality of weld can be achieved.Besides,centering and tack welding by laser beam should be avoided as centering point and tack-welding point can influence weld quality largely.
Laser conducting-limited welding of thin-wall HR-2 hydrogen-resistant stainless steel (HRSS) parts is discussed,processing parameters is studied,fluctuation of penetration and its influencing factors are analyzed,and measures to control fluctuation of penetration are presented.It is found that the maximal depth of fusion can be exceeded,and the fluctuation of penetration can be lessened,by taking measures such as low welding speed and preheating,when the HR-2 HRSS is welded by CO2 laser beam conduction-limited welding.With appropriate processing parameters and measures during laser conducting-limited welding of thin-wall HR-2 HRSS parts,depth of fusion can exceed 0.25mm,its fluctuation can be controlled in scope of ±10%,and good quality of weld can be achieved.Besides,centering and tack welding by laser beam should be avoided as centering point and tack-welding point can influence weld quality largely.
2005, 29(1): 32-34.
Abstract:
The movement of lightpen in a laser processing system is analysed in detail.The structure of DXF is analysed and introduced simply, a realizing way is brought forward for the exchanging interface of DXF data,whose advantages and disadvantages are compared with those of poltter(PLT) format in laser processing.The application of AutoCAD in laser processing is realized through the exchanging interface of DXF data,whose results are better than PLT format.
The movement of lightpen in a laser processing system is analysed in detail.The structure of DXF is analysed and introduced simply, a realizing way is brought forward for the exchanging interface of DXF data,whose advantages and disadvantages are compared with those of poltter(PLT) format in laser processing.The application of AutoCAD in laser processing is realized through the exchanging interface of DXF data,whose results are better than PLT format.
2005, 29(1): 35-37.
Abstract:
The field distribution of the gain glass waveguide is analyzed with beam propagation method (BMP),a numerical approach to calculate the field added gain gene is introduced.The variety of the field is discussed compared with the field added gain gene.The effects of pump power,Er-doped concentration on the field are discussed particularly,the figurs of the field distributing are achieved.
The field distribution of the gain glass waveguide is analyzed with beam propagation method (BMP),a numerical approach to calculate the field added gain gene is introduced.The variety of the field is discussed compared with the field added gain gene.The effects of pump power,Er-doped concentration on the field are discussed particularly,the figurs of the field distributing are achieved.
2005, 29(1): 38-39,55.
Abstract:
Ni-TiB2 ceramic-metal composite coating is cladded on the surface of 45# steel by CO2 laser melting a precursor mixture of nickel based alloy powder,boron and titanium powders.Microstructure of cladded layer is systematically studied by means of EPMA,TEM and XRD.The results show that the coating mainly consists of γ-Fe,γ-Ni dendrite solid solution and TiB2,TiB particles and a small a mount of Ni4B3.
Ni-TiB2 ceramic-metal composite coating is cladded on the surface of 45# steel by CO2 laser melting a precursor mixture of nickel based alloy powder,boron and titanium powders.Microstructure of cladded layer is systematically studied by means of EPMA,TEM and XRD.The results show that the coating mainly consists of γ-Fe,γ-Ni dendrite solid solution and TiB2,TiB particles and a small a mount of Ni4B3.
2005, 29(1): 40-42,65.
Abstract:
With the transfer matrix method,the transmission coefficient of a F-P cavity filter with a LiNbO3 optical waveguide is reasoned out.By computer simulation,the effects of structure parameters of the F-P cavity filter on the transmission light intensity,bandwidth and finess are analyzed.The results show that the transmission light intensity becomes weaker and bandwidth becomes wider with the increasing of propagation loss,and that with the increasing of reflectivity,the transmission light intensity becomes weaker and the bandwidth becomes narrower,however the finess becomes increscent.The optimizing parameters of the F-P cavity filter are given by considering the transmission light intensity and finess.
With the transfer matrix method,the transmission coefficient of a F-P cavity filter with a LiNbO3 optical waveguide is reasoned out.By computer simulation,the effects of structure parameters of the F-P cavity filter on the transmission light intensity,bandwidth and finess are analyzed.The results show that the transmission light intensity becomes weaker and bandwidth becomes wider with the increasing of propagation loss,and that with the increasing of reflectivity,the transmission light intensity becomes weaker and the bandwidth becomes narrower,however the finess becomes increscent.The optimizing parameters of the F-P cavity filter are given by considering the transmission light intensity and finess.
2005, 29(1): 43-45,86.
Abstract:
According to ITU proposal,microwave link is used to Ka band,the scheme of transparence transmitting microwave signal over laser link was designed,including direct modulation transmission and microwave frequency conversion transmission.The basic conditions of realizing the goal are indicated:light source of the transmitter is diode pumped solid-state laser (DPSSL) with high power and good quality of beams,and the optimum driver of the transmitter is a broadband LiNbO3 optical waveguide modulator.
According to ITU proposal,microwave link is used to Ka band,the scheme of transparence transmitting microwave signal over laser link was designed,including direct modulation transmission and microwave frequency conversion transmission.The basic conditions of realizing the goal are indicated:light source of the transmitter is diode pumped solid-state laser (DPSSL) with high power and good quality of beams,and the optimum driver of the transmitter is a broadband LiNbO3 optical waveguide modulator.
2005, 29(1): 46-49,76.
Abstract:
Nonlinear second-harmonic polarization matrix from the anisotropy magnetic-optical thin film,numbers and distribution of elements of the matrix at different symmetrical surfaces have been provided.The nonlinear polarization of the corresponding surface and the nonlinear second harmonic field aroused by the corresponding surface of evenly reflection space for the magnetic-optical thin film is also presented,when the magnetization strength of magnetic self-surplus parallel to the [001],[110] and [111] crystal surface respectively and the outside electric field does action to responding surface.The orientation angle of two possibilities of this harmonic smooth site is given.The cause factor and the reason of two possible orientations to correspondingly surface are analysized and discussed.
Nonlinear second-harmonic polarization matrix from the anisotropy magnetic-optical thin film,numbers and distribution of elements of the matrix at different symmetrical surfaces have been provided.The nonlinear polarization of the corresponding surface and the nonlinear second harmonic field aroused by the corresponding surface of evenly reflection space for the magnetic-optical thin film is also presented,when the magnetization strength of magnetic self-surplus parallel to the [001],[110] and [111] crystal surface respectively and the outside electric field does action to responding surface.The orientation angle of two possibilities of this harmonic smooth site is given.The cause factor and the reason of two possible orientations to correspondingly surface are analysized and discussed.
2005, 29(1): 50-51,100.
Abstract:
A new technique of fabricating stereo-rainbow holograms is presented which can record dynamic and spontaneous fluorescence objects by continuous laser.The technique also provides a new way to study the temperature distribution in a frame field, the concentration distribution of gals-flow and so on.Firstly, we take the primary stereoscopic picture of a dynamic and spontaneous fluorescence object by the linear lens array camera made by ourselves.Then continuous laser illuminates the primary stereoscopic picture and the stereo-rainbow hologram is fabricated.Here the linear lens array not only has imaging capability, but also acts as the slits of rainbow holography.In our experiments we fabricate stereo-rainbow holograms of candle's frame.The results prove that the technique is feasible.The paper presents the principle of the proposed technique and the experimental result.
A new technique of fabricating stereo-rainbow holograms is presented which can record dynamic and spontaneous fluorescence objects by continuous laser.The technique also provides a new way to study the temperature distribution in a frame field, the concentration distribution of gals-flow and so on.Firstly, we take the primary stereoscopic picture of a dynamic and spontaneous fluorescence object by the linear lens array camera made by ourselves.Then continuous laser illuminates the primary stereoscopic picture and the stereo-rainbow hologram is fabricated.Here the linear lens array not only has imaging capability, but also acts as the slits of rainbow holography.In our experiments we fabricate stereo-rainbow holograms of candle's frame.The results prove that the technique is feasible.The paper presents the principle of the proposed technique and the experimental result.
2005, 29(1): 52-55.
Abstract:
The effects of temperature on the performance of the twisted fiber loop are analyzed both theoretically and experimentally.The results reveal that there exists something like a pair of weak principal axes in the fiber,whose location may drift because of temperature change.It is found in the experiment that this drift may be significant when linear polarized light is used.The experiment also shows that SOP is little deteriorated when circular polarized light is used in a twisted fiber loop.
The effects of temperature on the performance of the twisted fiber loop are analyzed both theoretically and experimentally.The results reveal that there exists something like a pair of weak principal axes in the fiber,whose location may drift because of temperature change.It is found in the experiment that this drift may be significant when linear polarized light is used.The experiment also shows that SOP is little deteriorated when circular polarized light is used in a twisted fiber loop.
2005, 29(1): 56-58.
Abstract:
Based on the propagation law of partially coherent light,spectral changes of a polychromatic Gaussian-Schell model beam propagating in free space is studied.It is shown that the spectral splitting can take place in the near field,which is dependent on the spatial correlation and bandwidth of the spectral source and position parameters.The results are analyzed and illustrated with numerical examples.
Based on the propagation law of partially coherent light,spectral changes of a polychromatic Gaussian-Schell model beam propagating in free space is studied.It is shown that the spectral splitting can take place in the near field,which is dependent on the spatial correlation and bandwidth of the spectral source and position parameters.The results are analyzed and illustrated with numerical examples.
2005, 29(1): 59-61,89.
Abstract:
Using field coupling theory,the coupling efficiency of LD at different fiber inclined surface is discussed,and experimental results are presented too.The results show that the coupling efficiency is affected obviously by the fiber inclined angle,which can be improved if we choose the angle properly.
Using field coupling theory,the coupling efficiency of LD at different fiber inclined surface is discussed,and experimental results are presented too.The results show that the coupling efficiency is affected obviously by the fiber inclined angle,which can be improved if we choose the angle properly.
2005, 29(1): 62-65.
Abstract:
A series of pictures of return laser wave of "cat-eye" effect are recorded through the laser acquisition and tracking experiments, and a simple physical formulation of return photo source is brought forward.The experimental results offer reliable data for the next study and appliation of "cat-eye" effect.
A series of pictures of return laser wave of "cat-eye" effect are recorded through the laser acquisition and tracking experiments, and a simple physical formulation of return photo source is brought forward.The experimental results offer reliable data for the next study and appliation of "cat-eye" effect.
2005, 29(1): 66-67,112.
Abstract:
The scattering intensity and polarization properties of different size particles are simulated by the Ricatti-Bessel functions.As the size of particles increases,the scattering intensity increases;as the size of particles increases,the horizontal polarization becomes unsymmetrical while vertical polarization invariable;with the imaginary parts of complex refractive index increasing,the scattering intensity decreases.From these properties,various kinds of particles can be measured and taken apart.
The scattering intensity and polarization properties of different size particles are simulated by the Ricatti-Bessel functions.As the size of particles increases,the scattering intensity increases;as the size of particles increases,the horizontal polarization becomes unsymmetrical while vertical polarization invariable;with the imaginary parts of complex refractive index increasing,the scattering intensity decreases.From these properties,various kinds of particles can be measured and taken apart.
2005, 29(1): 68-71.
Abstract:
The analytical expressions for the mode coefficients and M2-factor of partially coherent flat-topped beams which can be combined by independent Hermite-Gaussian beams have been derived.The mode decomposition and mode composition of partially coherent flat-topped beams have been analyzed.The basis Gaussian mode decreases and the M2-factor increases with the beam order M and the parameter w0/ν0 increasing.The M2-factor and the rectangular shape of the flat-topped beams combined by the independent Hermite-Gaussian beams can not be obtained at the same time.If an approach rectangular shape of the intensity distribution of partially coherent flat-topped beams is desired,the M2-factor must be large.If the small value of M2-factor is required,the strictly rectangular shape of the intensity distribution can not be obtained.In many practical cases,the partially coherent flat-topped beams can be combined by the superposition of the independent Hermite-Gaussian beams with the proper choice of the beam waist and the power content.
The analytical expressions for the mode coefficients and M2-factor of partially coherent flat-topped beams which can be combined by independent Hermite-Gaussian beams have been derived.The mode decomposition and mode composition of partially coherent flat-topped beams have been analyzed.The basis Gaussian mode decreases and the M2-factor increases with the beam order M and the parameter w0/ν0 increasing.The M2-factor and the rectangular shape of the flat-topped beams combined by the independent Hermite-Gaussian beams can not be obtained at the same time.If an approach rectangular shape of the intensity distribution of partially coherent flat-topped beams is desired,the M2-factor must be large.If the small value of M2-factor is required,the strictly rectangular shape of the intensity distribution can not be obtained.In many practical cases,the partially coherent flat-topped beams can be combined by the superposition of the independent Hermite-Gaussian beams with the proper choice of the beam waist and the power content.
2005, 29(1): 72-73.
Abstract:
The air gap of polarization prism is influential to the transmissivity of this type of polarizer.Optimized design of the thickness of air gap is very useful to improve e-ray transmission in polarization prism.By means of the Glan-Taylor prism,based on the theory of Fresnel formula and multiple-beam interference,the calculation formulum of e-ray transmissivity in air-spaced prism is put forward.The law of the e-ray transmissivity varing with the air gap thickness is analyzed so that the optimum air gap thickness can be obtained to design an optimum polarizing prism.
The air gap of polarization prism is influential to the transmissivity of this type of polarizer.Optimized design of the thickness of air gap is very useful to improve e-ray transmission in polarization prism.By means of the Glan-Taylor prism,based on the theory of Fresnel formula and multiple-beam interference,the calculation formulum of e-ray transmissivity in air-spaced prism is put forward.The law of the e-ray transmissivity varing with the air gap thickness is analyzed so that the optimum air gap thickness can be obtained to design an optimum polarizing prism.
2005, 29(1): 74-76.
Abstract:
Based on the beam interferential theory of Fabry-Perot semiconductor laser,a bistable model of vertical cavity semiconductor optical amplifier (VCSOA) was established. According to recently experimental parameters,the bistable characteristics of VCSOA are investigated by simulation and three methods of controlling the width of hysteresis loop have been achieved:to enhance the bias current properly,increase top mirror reflectivity of VCSOA without changing the ratio of bias current versus threshold current or decrease initial phase detuning.All the methods can increase the loop width of the hysteresis loop.
Based on the beam interferential theory of Fabry-Perot semiconductor laser,a bistable model of vertical cavity semiconductor optical amplifier (VCSOA) was established. According to recently experimental parameters,the bistable characteristics of VCSOA are investigated by simulation and three methods of controlling the width of hysteresis loop have been achieved:to enhance the bias current properly,increase top mirror reflectivity of VCSOA without changing the ratio of bias current versus threshold current or decrease initial phase detuning.All the methods can increase the loop width of the hysteresis loop.
2005, 29(1): 77-79,93.
Abstract:
Based on the Fresnel diffraction integral,the analytical expression for the field distribution of converging spherical waves passing through an annular aperture is derived and some special cases are discussed.Numerical calculations are performed to show the dependence of intensity distribution on the Fresenl number and obscure ratio.In order to illustrate the valid range of the axial intensity expression and approximation formulae numerical results of both the methods are compared.
Based on the Fresnel diffraction integral,the analytical expression for the field distribution of converging spherical waves passing through an annular aperture is derived and some special cases are discussed.Numerical calculations are performed to show the dependence of intensity distribution on the Fresenl number and obscure ratio.In order to illustrate the valid range of the axial intensity expression and approximation formulae numerical results of both the methods are compared.
2005, 29(1): 80-81.
Abstract:
Based on the principle of polarizing modulation,a new method of phase retardation measurement and the experimental system are given.Investigative purpose is how to rise metrical precision and to rise metrical range.Measured result is metrical range from ultraviolet to near infrared and can measure other phase retardation.It is especially powerful for calibrating quarte-wave-plate and half-wave-plate,the metrical precision is less than 0.1%.
Based on the principle of polarizing modulation,a new method of phase retardation measurement and the experimental system are given.Investigative purpose is how to rise metrical precision and to rise metrical range.Measured result is metrical range from ultraviolet to near infrared and can measure other phase retardation.It is especially powerful for calibrating quarte-wave-plate and half-wave-plate,the metrical precision is less than 0.1%.
2005, 29(1): 82-86.
Abstract:
Based on the theory of quasi-three-level solid-state laser,the laser properties of LD edge-pumped Yb:YAG slab laser are studied with numerical calculation method.The laser output properties,temperature effect,optical distortion and doped concentration optimization are studied.The calculation results indicate that 100kW laser output can be achieved with Yb:YAG medium,whose size is about 130mm×60mm×3mm and Yb3+ concentration should be less than 1%.It is feasible to grow the crystal with size of 130mm×60mm×3mm,so Yb:YAG is a promising material used in the tactical laser weapons.
Based on the theory of quasi-three-level solid-state laser,the laser properties of LD edge-pumped Yb:YAG slab laser are studied with numerical calculation method.The laser output properties,temperature effect,optical distortion and doped concentration optimization are studied.The calculation results indicate that 100kW laser output can be achieved with Yb:YAG medium,whose size is about 130mm×60mm×3mm and Yb3+ concentration should be less than 1%.It is feasible to grow the crystal with size of 130mm×60mm×3mm,so Yb:YAG is a promising material used in the tactical laser weapons.
2005, 29(1): 87-89.
Abstract:
A stereo vision system used in construction robot is presented.Because two area CCDs are adapted in the system,it can orientate the space spot of laser spot center.Configuration of the system,math-model and computational equation is discussed.Using gray mention in data disposal,precise orientation of laser spot center is realized.The precision of the system can be up to 2% through the measuring of different sizes about ellipse,rectangle and triangle,and it isn't affected by the form of laser spot.The experiments illustrate that the system has fine stability.
A stereo vision system used in construction robot is presented.Because two area CCDs are adapted in the system,it can orientate the space spot of laser spot center.Configuration of the system,math-model and computational equation is discussed.Using gray mention in data disposal,precise orientation of laser spot center is realized.The precision of the system can be up to 2% through the measuring of different sizes about ellipse,rectangle and triangle,and it isn't affected by the form of laser spot.The experiments illustrate that the system has fine stability.
2005, 29(1): 90-93.
Abstract:
Several methods for extracting phase information based on spatial carrier fringe pattern are introduced,including sinusoid fitting method,convolution algorithm,Fourier transform method and wavelet transform method.In addition,comprehensive comparison between these methods is made.The fundamental limitations that lower the accuracy of Fourier transform method are examined,and improving approaches are discussed correspondingly.
Several methods for extracting phase information based on spatial carrier fringe pattern are introduced,including sinusoid fitting method,convolution algorithm,Fourier transform method and wavelet transform method.In addition,comprehensive comparison between these methods is made.The fundamental limitations that lower the accuracy of Fourier transform method are examined,and improving approaches are discussed correspondingly.
2005, 29(1): 94-97.
Abstract:
Preparation of Fe-based amorphous nanocrystalline soft magnetic materials has received much attention in a variety of fields.The double phase structure and the quality of Fe-based nanocrystalline soft magnetic materials and its application are introduced;the advantage and disadvantage are compared between the traditional annealing crystallization and preparation of the crystallization by laser.The significance,theoretical value and some unsolved problems about the technique of nanocrystallization by laser are presented.Finally,the need study key problems and direction of this preparation technology are presented.
Preparation of Fe-based amorphous nanocrystalline soft magnetic materials has received much attention in a variety of fields.The double phase structure and the quality of Fe-based nanocrystalline soft magnetic materials and its application are introduced;the advantage and disadvantage are compared between the traditional annealing crystallization and preparation of the crystallization by laser.The significance,theoretical value and some unsolved problems about the technique of nanocrystallization by laser are presented.Finally,the need study key problems and direction of this preparation technology are presented.
2005, 29(1): 98-100.
Abstract:
Various measurements of thin-film stress are summarized. The basic theory and measuring principle of laser macro deformation analysis (including laser interference measurement and laser beam deflexion measurement) that utilized substrate curvature measurement are analyzed; the precision of different measurements is evaluated. The precision of laser interference measurement nearly reaches 0.92% and the least stress that could be measured is 15.7MPa. Compared to laser interference measurement,the precision of laser beam deflexion measurement is low,it is about 2.12%,the least stress which could be measured is 25.5MPa,and space resolution is low as well,which is approximate 100μm.
Various measurements of thin-film stress are summarized. The basic theory and measuring principle of laser macro deformation analysis (including laser interference measurement and laser beam deflexion measurement) that utilized substrate curvature measurement are analyzed; the precision of different measurements is evaluated. The precision of laser interference measurement nearly reaches 0.92% and the least stress that could be measured is 15.7MPa. Compared to laser interference measurement,the precision of laser beam deflexion measurement is low,it is about 2.12%,the least stress which could be measured is 25.5MPa,and space resolution is low as well,which is approximate 100μm.
2005, 29(1): 101-103.
Abstract:
The polarizing prism film is optimized using K9 substrate and ZrO2,SiO2 thin film material.Designing aim is Tp>99% and Ts13 H3LH is best for the above design aim.The test shows that the film has excellent polarizing character.Then the influence of reference wavelength on polarizing film is discussed.
The polarizing prism film is optimized using K9 substrate and ZrO2,SiO2 thin film material.Designing aim is Tp>99% and Ts13 H3LH is best for the above design aim.The test shows that the film has excellent polarizing character.Then the influence of reference wavelength on polarizing film is discussed.
2005, 29(1): 104-105.
Abstract:
Based on Fresnel formula and electromagnetic thory the relationship between polarized light's incident azimuth and intermediary reflectance is studied.Then several special instances are introduced.
Based on Fresnel formula and electromagnetic thory the relationship between polarized light's incident azimuth and intermediary reflectance is studied.Then several special instances are introduced.
2005, 29(1): 106-108.
Abstract:
The simulation algorithm of flattened Gaussian beams(FGBs) passing through hard-aperture optics is improved,and an approximate closed-form propagation equation is derived,where a product of Fourier series and complex Gaussian function expansion is adapted to the window function of a hard-edged aperture. Numerical calculation results are compared with those obtained by direct integration of the Collins formula Wen's method.It is shown that the improved algorithm provides more accurate calculation results than the complex Gaussian function expansion,so long as the number of Fourier series is no less than 30.
The simulation algorithm of flattened Gaussian beams(FGBs) passing through hard-aperture optics is improved,and an approximate closed-form propagation equation is derived,where a product of Fourier series and complex Gaussian function expansion is adapted to the window function of a hard-edged aperture. Numerical calculation results are compared with those obtained by direct integration of the Collins formula Wen's method.It is shown that the improved algorithm provides more accurate calculation results than the complex Gaussian function expansion,so long as the number of Fourier series is no less than 30.
2005, 29(1): 109-112.
Abstract:
Taking the transmission effect of Gaussian pulse with initial chirp passing through a single-mode fiber as an example,the respective relations between linear initial chirp and first-order and high-order dispersion function of single-mode fiber are discussed systematically by means of theoretical analysis and numerical calculation.The sphere and conditions of applying initial chirp to dispersion compensation are pointed out.In a second order dispersion and third order dispersion compensation optical fiber links system,40Gbit/s Gaussian pulse transmission is simulated.It is concluded that as the second order dispersion compensation can avoid pulse broadening,the third order dispersion compensation can not only avoid pulse broadening but also eliminate pulse edges oscillating and temporal shift of pulse peak.
Taking the transmission effect of Gaussian pulse with initial chirp passing through a single-mode fiber as an example,the respective relations between linear initial chirp and first-order and high-order dispersion function of single-mode fiber are discussed systematically by means of theoretical analysis and numerical calculation.The sphere and conditions of applying initial chirp to dispersion compensation are pointed out.In a second order dispersion and third order dispersion compensation optical fiber links system,40Gbit/s Gaussian pulse transmission is simulated.It is concluded that as the second order dispersion compensation can avoid pulse broadening,the third order dispersion compensation can not only avoid pulse broadening but also eliminate pulse edges oscillating and temporal shift of pulse peak.
