Map
WeChat
Email alert
RSS1999 Vol. 23, No. 1
Display Method:
1999, 23(1): 1-3.
[Abstract]
[PDF 1221KB]
Abstract:
In order to obtain higher conversion effectiveness of secondary and triple harmonic.It is very important to accurately determine the orientation of the crystal axis,especially for KDP crystal.However,it all depends on the precise orientation of optical axis of the crystal.In general,the methods of X-ray diffraction or polarized wave interference are used,but these methods have their defects.Here,we employ a Nd:YAG laser beam to accurately inspect the orientation and to find o and e axis of KDP crystal.The experimental arrangement and results have been introduced in this paper.The method have higher measurement accuracy and can used in real-time inspecting.
In order to obtain higher conversion effectiveness of secondary and triple harmonic.It is very important to accurately determine the orientation of the crystal axis,especially for KDP crystal.However,it all depends on the precise orientation of optical axis of the crystal.In general,the methods of X-ray diffraction or polarized wave interference are used,but these methods have their defects.Here,we employ a Nd:YAG laser beam to accurately inspect the orientation and to find o and e axis of KDP crystal.The experimental arrangement and results have been introduced in this paper.The method have higher measurement accuracy and can used in real-time inspecting.
1999, 23(1): 4-6.
Abstract:
The experimental results of 2.1000μm Co:MgF2 pulsed laser operated at room-temterature end-pumped by 1.3414μm Nd:YAlO3 laser have been reported in this paper.Output energy of 279.4mJ has obtained with slope efficiency of 23%.The threshold energy of laser was 125mJ.
The experimental results of 2.1000μm Co:MgF2 pulsed laser operated at room-temterature end-pumped by 1.3414μm Nd:YAlO3 laser have been reported in this paper.Output energy of 279.4mJ has obtained with slope efficiency of 23%.The threshold energy of laser was 125mJ.
1999, 23(1): 6-10.
Abstract:
When zoom lens are used for military sighting,the drift of optical center caused by the change of focus length will reduce the sighting accuracy severely.In order to solve the problem,we employed two sets of compensation lenses,called conjugation lens sets,to eliminate the image plane shift.Also this paper discussed the miniaturization design,manufacture technology and automatic control of the system.
When zoom lens are used for military sighting,the drift of optical center caused by the change of focus length will reduce the sighting accuracy severely.In order to solve the problem,we employed two sets of compensation lenses,called conjugation lens sets,to eliminate the image plane shift.Also this paper discussed the miniaturization design,manufacture technology and automatic control of the system.
1999, 23(1): 11-15.
Abstract:
Whether the excellent properties of free electron laser can be brought into practice,it would ultimately depend upon the fact that the laser could be made compact.This paper proposed a improved and small-scale control system and accelerator for FEL, and introduced the compact Raman FEL.In control system,a new designed three-channel time-delay trigger utilized to trigger Marx generator to produce a high-voltage pulse.The electron beam source is a key component in our system.We employed a pseudospark discharge device to substitute the diode.The devise can obtain 10kA discharge current and current pulse half-width of 640ns at 300kV discharge voltage,the electron beam flow can achieve greater than 1kA.
Whether the excellent properties of free electron laser can be brought into practice,it would ultimately depend upon the fact that the laser could be made compact.This paper proposed a improved and small-scale control system and accelerator for FEL, and introduced the compact Raman FEL.In control system,a new designed three-channel time-delay trigger utilized to trigger Marx generator to produce a high-voltage pulse.The electron beam source is a key component in our system.We employed a pseudospark discharge device to substitute the diode.The devise can obtain 10kA discharge current and current pulse half-width of 640ns at 300kV discharge voltage,the electron beam flow can achieve greater than 1kA.
1999, 23(1): 16-19.
Abstract:
Based on the diffraction integral theory and numerical calculations,this paper analyzes the factors of influencing the small-scale non-uniformity of optical array systems,such as angle error of optical wedge,polarization control and regular phase distribution.The results are consistent with the experiments that the effective method is the proper angle error of optical wedge plus polarization control,and useful for design of optical uniform illumination system.
Based on the diffraction integral theory and numerical calculations,this paper analyzes the factors of influencing the small-scale non-uniformity of optical array systems,such as angle error of optical wedge,polarization control and regular phase distribution.The results are consistent with the experiments that the effective method is the proper angle error of optical wedge plus polarization control,and useful for design of optical uniform illumination system.
1999, 23(1): 20-22.
Abstract:
Through the ABCD method for light transformation,the radius of curvature of the outer surface of output mirror of a laser resonator is an important factor in influencing the beam property.In some practical applications, for example laser machining for large wok piece,we can desigh a proper radius of the curvature of the output mirror to improve the beam quality to be suitable for the application requirement.
Through the ABCD method for light transformation,the radius of curvature of the outer surface of output mirror of a laser resonator is an important factor in influencing the beam property.In some practical applications, for example laser machining for large wok piece,we can desigh a proper radius of the curvature of the output mirror to improve the beam quality to be suitable for the application requirement.
1999, 23(1): 23-25.
Abstract:
According to definition of narrow signal-noise ratio and analysis of measurement method,it is found that spectrum of the signal and data acquiring have the function with the measurement precision.This paper compared the double axis synchronous data acquiring,single axis identical voltage data acquiring and single axis identical interval data acquiring with each other,and found that the last one can obtain the highest test precision.
According to definition of narrow signal-noise ratio and analysis of measurement method,it is found that spectrum of the signal and data acquiring have the function with the measurement precision.This paper compared the double axis synchronous data acquiring,single axis identical voltage data acquiring and single axis identical interval data acquiring with each other,and found that the last one can obtain the highest test precision.
1999, 23(1): 26-29.
Abstract:
A new spherical-cylinder integrated lens is proposed which can deflect the optical axis to 90°,transform laser Gaussian beam in meridian section into parallel beam through refraction and reflection of spherical surfaces,and converge the sagittal beam into a real point outside of the lens though refraction and reflection of spherical surfaces and refraction of a cylinder surface.Its paraxial optical properties are analyzed and some constraint conditions are given.The lens has the advantages of low cost with volume production,large numerical aperture,which can find applications in the areas of transforming Gaussian or astigmatic laser beam into line beam such as cylinder interferometer,3-D profile measurement.
A new spherical-cylinder integrated lens is proposed which can deflect the optical axis to 90°,transform laser Gaussian beam in meridian section into parallel beam through refraction and reflection of spherical surfaces,and converge the sagittal beam into a real point outside of the lens though refraction and reflection of spherical surfaces and refraction of a cylinder surface.Its paraxial optical properties are analyzed and some constraint conditions are given.The lens has the advantages of low cost with volume production,large numerical aperture,which can find applications in the areas of transforming Gaussian or astigmatic laser beam into line beam such as cylinder interferometer,3-D profile measurement.
1999, 23(1): 29-33.
Abstract:
Based on birefringence laser frequency splitting principle.This paper introduced the experimental system for static and dynamic measurements.The static measurements include the angle detection with 0.3″ angle precision and the displacement detection with 10nm resolution.The dynamic detection can be utilize for detecting of the vibration frequency and amplitude with 15nm resolution at the range of 0.1 Hz～8kHz.The method has many advantages:higher sensitivity,wide frequency response range and good linearity.
Based on birefringence laser frequency splitting principle.This paper introduced the experimental system for static and dynamic measurements.The static measurements include the angle detection with 0.3″ angle precision and the displacement detection with 10nm resolution.The dynamic detection can be utilize for detecting of the vibration frequency and amplitude with 15nm resolution at the range of 0.1 Hz～8kHz.The method has many advantages:higher sensitivity,wide frequency response range and good linearity.
1999, 23(1): 34-37.
Abstract:
In this paper,using numerical solution method of vector diffraction theory,we discuss the dependence of reflectivity upon structural parameters of subwavelength grating,particularly upon substrate thickness.It can be used as the basis for design and fabrication of binary optical element with proper antireflection property.
In this paper,using numerical solution method of vector diffraction theory,we discuss the dependence of reflectivity upon structural parameters of subwavelength grating,particularly upon substrate thickness.It can be used as the basis for design and fabrication of binary optical element with proper antireflection property.
1999, 23(1): 38-41.
Abstract:
The quality factor of a laser beam often is characterized by parameter M2.In our measurement system,we employed a CCD sensor to detect the beam profiles at different location in beam propagation direction,then utilized the data identification to calculate factor M2.This paper give out the measurement results and tolerance limits.
The quality factor of a laser beam often is characterized by parameter M2.In our measurement system,we employed a CCD sensor to detect the beam profiles at different location in beam propagation direction,then utilized the data identification to calculate factor M2.This paper give out the measurement results and tolerance limits.
1999, 23(1): 42-45.
Abstract:
Focusing of Gaussian beam by an apertured lens with spherical aberration is calculated,based on Huygens-Fresnel diffraction integral.The numerical results show that,when the coefficient of the spherical aberration is negative,one can obtain flattened laser intensity profile in two positions along the focused field.The effect of the limited aperture of the lens on the flattened laser intensity profile is investigated.It is shown that when Fresnel number of the lens become small,the positions where flattened laser intensity profile occur shift towards the focusing lens,and the lens with negative spherical aberration may be a simple approach for achieving flattened laser irradiance.
Focusing of Gaussian beam by an apertured lens with spherical aberration is calculated,based on Huygens-Fresnel diffraction integral.The numerical results show that,when the coefficient of the spherical aberration is negative,one can obtain flattened laser intensity profile in two positions along the focused field.The effect of the limited aperture of the lens on the flattened laser intensity profile is investigated.It is shown that when Fresnel number of the lens become small,the positions where flattened laser intensity profile occur shift towards the focusing lens,and the lens with negative spherical aberration may be a simple approach for achieving flattened laser irradiance.
1999, 23(1): 46-50.
Abstract:
The receiver field of view is a characteristic parameter of lidar and defined by its angular coverage.When laser beam propagates in liquid medium,received signal has the relation with the receiver field of view and beam scattering.We employ a improved semi-analytic Monte-Carlo method to simulate the lidar receiver signal.In order to obtain higher simulation accuracy,we use the modified Henyey-Greenstein function to express the scattering phase function,insert weight collision coefficient of photon,and relax the critical limit in order to increase the calculation efficiency of photon.As known from the simulation results,different receiver field of view produce greatly different received signal waveform.Finally,we concluded that the optimum receiver signal can be obtain when receiver field of view is in the range of 20～30mrad.
The receiver field of view is a characteristic parameter of lidar and defined by its angular coverage.When laser beam propagates in liquid medium,received signal has the relation with the receiver field of view and beam scattering.We employ a improved semi-analytic Monte-Carlo method to simulate the lidar receiver signal.In order to obtain higher simulation accuracy,we use the modified Henyey-Greenstein function to express the scattering phase function,insert weight collision coefficient of photon,and relax the critical limit in order to increase the calculation efficiency of photon.As known from the simulation results,different receiver field of view produce greatly different received signal waveform.Finally,we concluded that the optimum receiver signal can be obtain when receiver field of view is in the range of 20～30mrad.
1999, 23(1): 50-52.
Abstract:
This paper theorectically analyzed the ranging error of a pulse laser ranger.We considered the main factors of ranging circuits,such as the stability of oscillating frequency of crystal oscillator,response time of receiving system and width of laser pulse.The ranging error can be controlled in the range -5m～10m for design of a pulse laser ranger.
This paper theorectically analyzed the ranging error of a pulse laser ranger.We considered the main factors of ranging circuits,such as the stability of oscillating frequency of crystal oscillator,response time of receiving system and width of laser pulse.The ranging error can be controlled in the range -5m～10m for design of a pulse laser ranger.
1999, 23(1): 53-56.
Abstract:
Utilizing an image fiber bundle to transmit images is a very useful technique.Here,one of the most important image transmission performances is the term crosstalk.Up to date,the study of flexible image bundles has not been quantified.We demonstrated the expression of the term crosstalk and use an optical video system to quantitatively measure the crosstalk ratio in flexible fiber bundle.Additionally,the static modulation transmission function(MTF) measurement together with visual inspection was used to analyze the effects of the term crosstalk to the image transmission performances of the image fiber bundle,such as image contrast,distinguish ability and image transmittivity.Finnally,this paper introduced the experimental results of image transmission performances of the different kinds of image fiber bundles.
Utilizing an image fiber bundle to transmit images is a very useful technique.Here,one of the most important image transmission performances is the term crosstalk.Up to date,the study of flexible image bundles has not been quantified.We demonstrated the expression of the term crosstalk and use an optical video system to quantitatively measure the crosstalk ratio in flexible fiber bundle.Additionally,the static modulation transmission function(MTF) measurement together with visual inspection was used to analyze the effects of the term crosstalk to the image transmission performances of the image fiber bundle,such as image contrast,distinguish ability and image transmittivity.Finnally,this paper introduced the experimental results of image transmission performances of the different kinds of image fiber bundles.
1999, 23(1): 57-61.
Abstract:
We use finite element method to calculate temperature field and thermal stress field for Al2O3/Ti system FGM in the process of laser sintering.The temperature of the different layers of the sintering sample was measured with the thermocouples.The results show that the temperature drop between the laser irradiating surface(Al2O3/Ti layer) and the back surface(Ti layer) was 325℃,and the temperature gradient was more precipitous in Al2O3 ceramic layer than in Ti metal layer.We defined the parameter p,called component gradient of FGM sample,to indicate the level of the temperature gradient in ceramic Al2O3 layer.The thermal residual stress distribution mainly was dependent on the value of p.The axial shear stress occurred near the radial free edge,and transformed from compressive stress to tensile stress along with the increasing of p from less than 0.5 to greater than 0.5.The maximum radial stress occurred in the transition region between pure Al2O3 layer and graded interlayer.The distribution of circumferential stress was similar to radial stress distribution.All of the component of the thermal residual stress got the minimum when p=0.5.
We use finite element method to calculate temperature field and thermal stress field for Al2O3/Ti system FGM in the process of laser sintering.The temperature of the different layers of the sintering sample was measured with the thermocouples.The results show that the temperature drop between the laser irradiating surface(Al2O3/Ti layer) and the back surface(Ti layer) was 325℃,and the temperature gradient was more precipitous in Al2O3 ceramic layer than in Ti metal layer.We defined the parameter p,called component gradient of FGM sample,to indicate the level of the temperature gradient in ceramic Al2O3 layer.The thermal residual stress distribution mainly was dependent on the value of p.The axial shear stress occurred near the radial free edge,and transformed from compressive stress to tensile stress along with the increasing of p from less than 0.5 to greater than 0.5.The maximum radial stress occurred in the transition region between pure Al2O3 layer and graded interlayer.The distribution of circumferential stress was similar to radial stress distribution.All of the component of the thermal residual stress got the minimum when p=0.5.
1999, 23(1): 62-64.
Abstract:
This paper analyzed the medical mechanism of Nd:YAP laser cauterization to pulpitis and periodontitis with one fill method,and pointed out that also it is a new problem,but it is worth to continually research the medical treatment method.
This paper analyzed the medical mechanism of Nd:YAP laser cauterization to pulpitis and periodontitis with one fill method,and pointed out that also it is a new problem,but it is worth to continually research the medical treatment method.
