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RSS2004 Vol. 28, No. 4
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2004, 28(4): 337-339.
[Abstract]
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Abstract:
In the approximation of the modulation process of two scale-eddies (inner-scale and outer-scale eddies) for light wave propagation in turbulent atmosphere,we study the wave structure function(WSF) used to calculate the mutual coherence function from which the transverse coherence length can readily be determined for an infinite plane wave or spherical wave.Analytical expressions are derived by means of the development of the modulation model of the power spectral density of the refractive-index fluctuations which include the factor of small-scale and large-scale sizes turbulence eddies for the wave structure function associated with the propagation of infinite plane waves and spherical waves through isotropic and homogeneous turbulence.For computational case,the approximation expressions for the structure function of infinite plane waves and spherical waves propagating through isotropic and homogeneous turbulence are also developed by simple interpolation method,whose error is less than 2%.
In the approximation of the modulation process of two scale-eddies (inner-scale and outer-scale eddies) for light wave propagation in turbulent atmosphere,we study the wave structure function(WSF) used to calculate the mutual coherence function from which the transverse coherence length can readily be determined for an infinite plane wave or spherical wave.Analytical expressions are derived by means of the development of the modulation model of the power spectral density of the refractive-index fluctuations which include the factor of small-scale and large-scale sizes turbulence eddies for the wave structure function associated with the propagation of infinite plane waves and spherical waves through isotropic and homogeneous turbulence.For computational case,the approximation expressions for the structure function of infinite plane waves and spherical waves propagating through isotropic and homogeneous turbulence are also developed by simple interpolation method,whose error is less than 2%.
2004, 28(4): 340-343.
Abstract:
In this paper the mechanism of the laser bending of tube parts is elaborated.And the bending rules are obtained through the experiment.Laser tube bending is a flexible forming process by which metal tube can be bent without external force.It is generally known that laser bending of tubes is achieved through upsetting mechanism.The scanned region of the tube is heated almost homogeneously in the thickness direction,and undergoes compressive plastic deformation and wall thickening due to restriction on thermal expansion by the surrounding material.The major problem in the study of laser bending is to understand the temperature and stress-strain distribution at different process parameters and scanning paths.The process parameters influencing the laser bending parts of tube mainly include laser power,scanning angle and numbers,facular diameter and scanning speed.With the help of the experiment the respective influence of the five process parameters on the bending angle is studied. Within the range of some fixed value given,the bending angle can be increased by the following means:increasing the laser power,scanning angle and scanning numbers and decreasing the scanning speed.
In this paper the mechanism of the laser bending of tube parts is elaborated.And the bending rules are obtained through the experiment.Laser tube bending is a flexible forming process by which metal tube can be bent without external force.It is generally known that laser bending of tubes is achieved through upsetting mechanism.The scanned region of the tube is heated almost homogeneously in the thickness direction,and undergoes compressive plastic deformation and wall thickening due to restriction on thermal expansion by the surrounding material.The major problem in the study of laser bending is to understand the temperature and stress-strain distribution at different process parameters and scanning paths.The process parameters influencing the laser bending parts of tube mainly include laser power,scanning angle and numbers,facular diameter and scanning speed.With the help of the experiment the respective influence of the five process parameters on the bending angle is studied. Within the range of some fixed value given,the bending angle can be increased by the following means:increasing the laser power,scanning angle and scanning numbers and decreasing the scanning speed.
2004, 28(4): 344-345,351.
Abstract:
In order to obtain the absolute photonic band gaps,we design a two-dimension cubic compound lattices made of dielectric cylinders with an air hole in their centers and study its photonic band structures with the plane-wave method. An absolute photonic band gaps common to E and H polarized waves are created when given proper structure parameters,which tells us that absolute photonic band gaps can be created from a simple lattice.
In order to obtain the absolute photonic band gaps,we design a two-dimension cubic compound lattices made of dielectric cylinders with an air hole in their centers and study its photonic band structures with the plane-wave method. An absolute photonic band gaps common to E and H polarized waves are created when given proper structure parameters,which tells us that absolute photonic band gaps can be created from a simple lattice.
2004, 28(4): 346-351.
Abstract:
The development status of patents in China and America from 1996 to 2002 is reviewed and compared.There is a big difference about the number and quality of patents between China and America.It is found that laser welding,cutting,drilling,marking and annealing were still the main stream for technology creation in the past 7 years,which may even expand bigger with the improvement of laser devices and development of new types of lasers.There are two important points to develop laser processing industry in China:the first is developing new technology geared to the needs of market,the second is strengthening the consciousness of patents and how to use intelligent right to develop new products.
The development status of patents in China and America from 1996 to 2002 is reviewed and compared.There is a big difference about the number and quality of patents between China and America.It is found that laser welding,cutting,drilling,marking and annealing were still the main stream for technology creation in the past 7 years,which may even expand bigger with the improvement of laser devices and development of new types of lasers.There are two important points to develop laser processing industry in China:the first is developing new technology geared to the needs of market,the second is strengthening the consciousness of patents and how to use intelligent right to develop new products.
2004, 28(4): 352-354,362.
Abstract:
The behavior of graphite phase in the laser hardening layer of gray iron is deeply studied by means of optical microscope and electron probe.Results show that the graphite dissolves completely and diffuses uniformly in the melt layer;the graphite in the phase transformation hardening layer dissolves partly,but the diffusion isn't uniformity;and that the graphite in the transition layer does not dissolve basically. It can be concluded that the behavior of graphite has close relation with the hardening layer structure and the effect of hardening.
The behavior of graphite phase in the laser hardening layer of gray iron is deeply studied by means of optical microscope and electron probe.Results show that the graphite dissolves completely and diffuses uniformly in the melt layer;the graphite in the phase transformation hardening layer dissolves partly,but the diffusion isn't uniformity;and that the graphite in the transition layer does not dissolve basically. It can be concluded that the behavior of graphite has close relation with the hardening layer structure and the effect of hardening.
2004, 28(4): 355-358.
Abstract:
The research development of integrated collinear acousto-optic devices based on LiNbO3 waveguide is reviewed.The application of such devices in light deflection and modulation,signal processing and optical calculating is described.The future development of research for these devices is introduced briefly.
The research development of integrated collinear acousto-optic devices based on LiNbO3 waveguide is reviewed.The application of such devices in light deflection and modulation,signal processing and optical calculating is described.The future development of research for these devices is introduced briefly.
2004, 28(4): 359-362.
Abstract:
Discrimination,reflectivity and FSW(free spectrum width),which are determined by the geometric attenuation factor of optic field and reflectivity of two ends greatly,are the important factors of FFP(fiber Fabry-Perot).Because of the imprecision of the old attenuation factor,which is based on identical beam model,a new model based on Gaussian beams is provided,and the equation of which is found.Then the influence of cavity length and refrectivity of ends to discrimination and reflectivity of FFP is analysed deeply. Conclusively,a FFP wavelength demodulator is designed for optic fiber grating.
Discrimination,reflectivity and FSW(free spectrum width),which are determined by the geometric attenuation factor of optic field and reflectivity of two ends greatly,are the important factors of FFP(fiber Fabry-Perot).Because of the imprecision of the old attenuation factor,which is based on identical beam model,a new model based on Gaussian beams is provided,and the equation of which is found.Then the influence of cavity length and refrectivity of ends to discrimination and reflectivity of FFP is analysed deeply. Conclusively,a FFP wavelength demodulator is designed for optic fiber grating.
2004, 28(4): 363-365.
Abstract:
In this article,the conversion efficiency of the third harmonic generation induced by second-order cascading in nonlinear photonic crystals is analysed when quasi-phase matching is satisfied. The numerical calculation shows that the conversion efficiency of third harmonic generation is strongly modulated by second harmonic signal in input light. If the ratio of the intensity and the primary phase of second harmonic signal and fundamental light satisfy certain condition,a high conversion efficiency of the third harmonic generation can be found in a wide scale of input intensity.
In this article,the conversion efficiency of the third harmonic generation induced by second-order cascading in nonlinear photonic crystals is analysed when quasi-phase matching is satisfied. The numerical calculation shows that the conversion efficiency of third harmonic generation is strongly modulated by second harmonic signal in input light. If the ratio of the intensity and the primary phase of second harmonic signal and fundamental light satisfy certain condition,a high conversion efficiency of the third harmonic generation can be found in a wide scale of input intensity.
2004, 28(4): 366-369.
Abstract:
In this paper,the properties of ASE gain flattened of EDFA are studied based on energy level and particle number shifting of EDFA both theoretically and experimentally.The ASE expanded spectrum 5nm and gain flattened 1dB～2dB of EDFA have obtained using a long period fiber grating.The optimum results of EDFA parameters are measured with the pump energy rightly.The relation curve of the usable band width and gain energy versus pump energy has obtained.
In this paper,the properties of ASE gain flattened of EDFA are studied based on energy level and particle number shifting of EDFA both theoretically and experimentally.The ASE expanded spectrum 5nm and gain flattened 1dB～2dB of EDFA have obtained using a long period fiber grating.The optimum results of EDFA parameters are measured with the pump energy rightly.The relation curve of the usable band width and gain energy versus pump energy has obtained.
2004, 28(4): 370-372,416.
Abstract:
By using a numerically controlled 2-D shifter,measurement data of PSD are obtained and then artificial neural networks are used for non-linearity correction of two dimensional PSD. When a light point moves in the detective area of PSD,the coordinates of the point at different positions are used as designed output of the networks and the output coordinates of the PSD are used as learning input of the networks,and a learning procedure is carried out. According to the ability of non-linear mapping of artificial neural networks,a linear relationship between input and output of the networks is set up after learning. Results show that learned networks can correct any non-linearity error in real time.
By using a numerically controlled 2-D shifter,measurement data of PSD are obtained and then artificial neural networks are used for non-linearity correction of two dimensional PSD. When a light point moves in the detective area of PSD,the coordinates of the point at different positions are used as designed output of the networks and the output coordinates of the PSD are used as learning input of the networks,and a learning procedure is carried out. According to the ability of non-linear mapping of artificial neural networks,a linear relationship between input and output of the networks is set up after learning. Results show that learned networks can correct any non-linearity error in real time.
2004, 28(4): 373-375,400.
Abstract:
Under the approximation of geometric optics,the axial force exerted on the Mie microsphere particles is simulated.The capture range and the curves of simulation are shown.The results show that decreasing focus spot radius leads to deeper optical traps and that relative refractive index,laser wavelength and power also have some effect on optical trap,which give some reliance on choosing parameters in experiments.
Under the approximation of geometric optics,the axial force exerted on the Mie microsphere particles is simulated.The capture range and the curves of simulation are shown.The results show that decreasing focus spot radius leads to deeper optical traps and that relative refractive index,laser wavelength and power also have some effect on optical trap,which give some reliance on choosing parameters in experiments.
2004, 28(4): 376-378,405.
Abstract:
The relation between on-off gain of forward pumped Raman fiber amplifier and several important parameters,including Raman gain coefficient,pump power,fiber length,fiberloss,efficient area,etc.,is investigated by numerical simulation.The results are compared with the analytic solution under small signal.At last,several methods improving the on-off gain of Raman fiber amplifier are presented.
The relation between on-off gain of forward pumped Raman fiber amplifier and several important parameters,including Raman gain coefficient,pump power,fiber length,fiberloss,efficient area,etc.,is investigated by numerical simulation.The results are compared with the analytic solution under small signal.At last,several methods improving the on-off gain of Raman fiber amplifier are presented.
2004, 28(4): 379-382,409.
Abstract:
Based on the rate equations and light propagation equations,the model of Er3+/Yb3+ co-doped double clad fiber amplifiers has been discussed,and the population distribution characteristics of Er3+ upper level in Er3+/Yb3+ co-doped double clad fiber amplifier pumped at 980nm bands have been analyzed by using the results of numerical simulation.The normalized population distribution curves of Er3+ upper level have been obtained under two different pump schemes,namely co- and counter-propagations. The distribution characteristic of signal has also been analyzed by using the normalized population distribution curves of Er3+ upper level.
Based on the rate equations and light propagation equations,the model of Er3+/Yb3+ co-doped double clad fiber amplifiers has been discussed,and the population distribution characteristics of Er3+ upper level in Er3+/Yb3+ co-doped double clad fiber amplifier pumped at 980nm bands have been analyzed by using the results of numerical simulation.The normalized population distribution curves of Er3+ upper level have been obtained under two different pump schemes,namely co- and counter-propagations. The distribution characteristic of signal has also been analyzed by using the normalized population distribution curves of Er3+ upper level.
2004, 28(4): 383-386,430.
Abstract:
Development of fiber optical parametric amplifier(OPAs) is very fast in recent years.On one hand,this paper analyzes several important efficient techniques for improving the peak gain,expanding the gain bandwidth,reducing the polarization sensitivity of fiber OPAs.On the other hand,some typical applications such as lumped amplifying,transparent wavelength conversion,RZ pulse generation,O-TDM switch,all optical sampling,all-optical erasable storage buffer,3R regeneration are fully summarized.Fiber OPAs would be abroad and significantly used in DWDM and all-optical net(AON).
Development of fiber optical parametric amplifier(OPAs) is very fast in recent years.On one hand,this paper analyzes several important efficient techniques for improving the peak gain,expanding the gain bandwidth,reducing the polarization sensitivity of fiber OPAs.On the other hand,some typical applications such as lumped amplifying,transparent wavelength conversion,RZ pulse generation,O-TDM switch,all optical sampling,all-optical erasable storage buffer,3R regeneration are fully summarized.Fiber OPAs would be abroad and significantly used in DWDM and all-optical net(AON).
The temperature dependence of incoherently coupled bright-dark screening-photovoltaic solition pairs
2004, 28(4): 387-389,396.
Abstract:
Neglecting the diffusion effect,the temperature dependence of the incoherently coupled bright-dark screening-photovoltaic pairs are in the photovoltaic-photorefractive crystals and applied delectric are discussed.For a stable incoherently coupled bright-dark screening-photovoltaic solition pairs are originally formed in a crystal at a given temperature,when the crystal temperature changes,it will evolve into another stable solition pairs.The spatial shape of a stable incoherently coupled bright-dark screening-photovoltaic solition pairs can be reshaped by adjusting the crystals temperature.
Neglecting the diffusion effect,the temperature dependence of the incoherently coupled bright-dark screening-photovoltaic pairs are in the photovoltaic-photorefractive crystals and applied delectric are discussed.For a stable incoherently coupled bright-dark screening-photovoltaic solition pairs are originally formed in a crystal at a given temperature,when the crystal temperature changes,it will evolve into another stable solition pairs.The spatial shape of a stable incoherently coupled bright-dark screening-photovoltaic solition pairs can be reshaped by adjusting the crystals temperature.
2004, 28(4): 390-393.
Abstract:
On basis of geometry optics,we designed unstable resonators with Gaussian and super-Gaussian variable reflectance mirrors.The mode equations in the cavity is obtained by FFT expressions so as to be easily solved.The 3-D optic intensity distributions in near and far field,as well as reflecting from reflectors,output mirrors,are numerically calculated.These results can be used as available references for design of unstable resonators with variable reflectance mirrors.
On basis of geometry optics,we designed unstable resonators with Gaussian and super-Gaussian variable reflectance mirrors.The mode equations in the cavity is obtained by FFT expressions so as to be easily solved.The 3-D optic intensity distributions in near and far field,as well as reflecting from reflectors,output mirrors,are numerically calculated.These results can be used as available references for design of unstable resonators with variable reflectance mirrors.
2004, 28(4): 394-396.
Abstract:
The optical system has been established in which the change of polarization state for magneto-optic crystal can be measured.In the system,the rotation angles for two types of magneto-optic crystals (BiCaInVIG and GdYBiIG) used in optical communication system have been measured at oblique incidence.The experiment results show that there is anisotropic distribution of Faraday effect in the magneto-optic crystal.
The optical system has been established in which the change of polarization state for magneto-optic crystal can be measured.In the system,the rotation angles for two types of magneto-optic crystals (BiCaInVIG and GdYBiIG) used in optical communication system have been measured at oblique incidence.The experiment results show that there is anisotropic distribution of Faraday effect in the magneto-optic crystal.
2004, 28(4): 397-400.
Abstract:
The SBR is applied for mode-locking in the femtosecond solid-state lasers to obtain the steady mode-locked pulses.In this paper,the structure and the spectrum of the saturable Bragg reflector are generalized in detail,and the relation between the absorption coefficient,saturation intensity and the inherent parameters of the SBR is derived from the density matrix equations.The basic mode-locked mechanism of the SBR has been analyzed and the fundamental mode-locked conditions of SBR in the solid-state lasers has been obtained.It is found that the SBR can be used in the mode-locking of the femtosecond solid-state lasers and it can enhance the properties of mode-locked pulses.
The SBR is applied for mode-locking in the femtosecond solid-state lasers to obtain the steady mode-locked pulses.In this paper,the structure and the spectrum of the saturable Bragg reflector are generalized in detail,and the relation between the absorption coefficient,saturation intensity and the inherent parameters of the SBR is derived from the density matrix equations.The basic mode-locked mechanism of the SBR has been analyzed and the fundamental mode-locked conditions of SBR in the solid-state lasers has been obtained.It is found that the SBR can be used in the mode-locking of the femtosecond solid-state lasers and it can enhance the properties of mode-locked pulses.
2004, 28(4): 401-403,423.
Abstract:
The thin film polarizing beam splitting prism is designed based on MacNeille type by using LaK2 substrate and ZrO2,SiO2 thin film material.The test show that the prism has excellent polarizing character,the splitting character is good at the range of 550nm～750nm,the extinction ratio is 2.1×10-4,the extinction ratio turns big when the incident angle change small.
The thin film polarizing beam splitting prism is designed based on MacNeille type by using LaK2 substrate and ZrO2,SiO2 thin film material.The test show that the prism has excellent polarizing character,the splitting character is good at the range of 550nm～750nm,the extinction ratio is 2.1×10-4,the extinction ratio turns big when the incident angle change small.
2004, 28(4): 404-405.
Abstract:
Using transversal pulse pre-ionization transversal pulse pre-ionization,a small diffusion-cooled longitudinal pulsed discharge CO2 laser is described.15mJ pulse energy with 375W pulse peak power has been achieved up with PRR to 56Hz from a discharge tube of 7.5mm inner diameter and 50cm long.The pre-ionization electrodes are designed as helical to improve the laser beam quality.
Using transversal pulse pre-ionization transversal pulse pre-ionization,a small diffusion-cooled longitudinal pulsed discharge CO2 laser is described.15mJ pulse energy with 375W pulse peak power has been achieved up with PRR to 56Hz from a discharge tube of 7.5mm inner diameter and 50cm long.The pre-ionization electrodes are designed as helical to improve the laser beam quality.
2004, 28(4): 406-409.
Abstract:
Gray-scale mask method is an active groping facture idea of binary optics at present.For more utility,some difficult questions such as mask patterns' making and technique are being studied in-depth based on the manufacturing method for gray-scale masks using special light modulator.At the same time,some gray-scale masks of normal binary optical elements have been actually fabricated.
Gray-scale mask method is an active groping facture idea of binary optics at present.For more utility,some difficult questions such as mask patterns' making and technique are being studied in-depth based on the manufacturing method for gray-scale masks using special light modulator.At the same time,some gray-scale masks of normal binary optical elements have been actually fabricated.
2004, 28(4): 410-413.
Abstract:
The experiment of the laser-induced diffraction in poly-phenylene vinylene(PPV) derivative/chloroform solution is made by using the 532nm continuous laser.According to the number of the diffraction rings,the Kerr constant and nonlinear refractive index of the material can be estimated.It is found that:when input-power reaches the threshold 0.77mW but less than 3.36mW,it is mainly Kerr effect that causes the diffraction rings owing to spatial self-phase modulation while the Gaussian beam passing through the nonlinear medium.Therefore,the Kerr constant γ of PPV/chloroform solution (absorption cofficient 4.76cm-1 at 532nm) is about 5.55×10-10m2/W and the nonlinear refractive index n2 is probably 9.21×10-4esu.But as input-power is increased,diffraction rings caused by thermo-optic effect submerge diffraction rings caused by Kerr effect.
The experiment of the laser-induced diffraction in poly-phenylene vinylene(PPV) derivative/chloroform solution is made by using the 532nm continuous laser.According to the number of the diffraction rings,the Kerr constant and nonlinear refractive index of the material can be estimated.It is found that:when input-power reaches the threshold 0.77mW but less than 3.36mW,it is mainly Kerr effect that causes the diffraction rings owing to spatial self-phase modulation while the Gaussian beam passing through the nonlinear medium.Therefore,the Kerr constant γ of PPV/chloroform solution (absorption cofficient 4.76cm-1 at 532nm) is about 5.55×10-10m2/W and the nonlinear refractive index n2 is probably 9.21×10-4esu.But as input-power is increased,diffraction rings caused by thermo-optic effect submerge diffraction rings caused by Kerr effect.
2004, 28(4): 414-416.
Abstract:
The scattering light of bubble is analysed from the point of view of geometry optics,from which it is concluded that the fluctuation of light intensity has some relation with the diameter of bubbles.Using this relation and adopting the light intensity detecting method,the light intensity through the wall of bubbles is collected,the dimension of bubbles and its distribution is deduced based on the analysis of fluctuatation of light intensity.This method is brief and needs less data than other detecting methods.
The scattering light of bubble is analysed from the point of view of geometry optics,from which it is concluded that the fluctuation of light intensity has some relation with the diameter of bubbles.Using this relation and adopting the light intensity detecting method,the light intensity through the wall of bubbles is collected,the dimension of bubbles and its distribution is deduced based on the analysis of fluctuatation of light intensity.This method is brief and needs less data than other detecting methods.
2004, 28(4): 417-419.
Abstract:
According to a theoretical model of making high quality probe,we make the nanometric optical fiber probe that can be utilized in optical fiber biological sensor with tube etching method.This method is easy to manipulate and produce with relatively low cost.Moreover,it is not so sensitive with the experimental environment,so the repeative rate of making optical fiber probe is relatively high.The tips diameters are less than 50nm,and the taper angle 45°.We finally analyze and discuss the shape of optical fiber probe under the effect of some uncertain factors during the tube etching experiment.
According to a theoretical model of making high quality probe,we make the nanometric optical fiber probe that can be utilized in optical fiber biological sensor with tube etching method.This method is easy to manipulate and produce with relatively low cost.Moreover,it is not so sensitive with the experimental environment,so the repeative rate of making optical fiber probe is relatively high.The tips diameters are less than 50nm,and the taper angle 45°.We finally analyze and discuss the shape of optical fiber probe under the effect of some uncertain factors during the tube etching experiment.
2004, 28(4): 420-423.
Abstract:
The intensity and angular distribution of Brillouin scattering have got much attention with the development of light scattering detection technique,especially in ocean detection with Brillouin scattering.The Brillouin scattering cross section is deduced with classical electromagnetic theory,and improved when we combine quantum electrodynamics with classical electromagnetic theory.At last,both ways in depicting the physics process of Brillouin scattering underwater are compared and discussed intensively.
The intensity and angular distribution of Brillouin scattering have got much attention with the development of light scattering detection technique,especially in ocean detection with Brillouin scattering.The Brillouin scattering cross section is deduced with classical electromagnetic theory,and improved when we combine quantum electrodynamics with classical electromagnetic theory.At last,both ways in depicting the physics process of Brillouin scattering underwater are compared and discussed intensively.
2004, 28(4): 424-426.
Abstract:
In order to make the exit beam of a retarder to deflect 90°,a new method of the design of a retarder is given.Using combination of a rhombus retarder and a parallel plate retarder to make the beam deflect 90° on the rhombus retarder for total reflecton and make the retarder have a function of delay.Testing shows that the error of the retarder is permissible,which proves the design is reasonable.
In order to make the exit beam of a retarder to deflect 90°,a new method of the design of a retarder is given.Using combination of a rhombus retarder and a parallel plate retarder to make the beam deflect 90° on the rhombus retarder for total reflecton and make the retarder have a function of delay.Testing shows that the error of the retarder is permissible,which proves the design is reasonable.
2004, 28(4): 427-430.
Abstract:
Based on the coupled nonlinear Schrdinger equation,conditions and gain spectra of modulation instability(MI) induced by cross-phase modulation(XPM) of two optical waves in the optical fiber are analyzed in detail. The results show that when one of the two optical waves propagates in the normal group-velocity dispersion (GVD) regime and the other in the anomalous regime,depending on parameters of the two optical waves,perturbation gain spectra may take three possible forms. Under certain circumstances,it is even possible that there are two forms of gain spectra within certain range of perturbation frequency.
Based on the coupled nonlinear Schrdinger equation,conditions and gain spectra of modulation instability(MI) induced by cross-phase modulation(XPM) of two optical waves in the optical fiber are analyzed in detail. The results show that when one of the two optical waves propagates in the normal group-velocity dispersion (GVD) regime and the other in the anomalous regime,depending on parameters of the two optical waves,perturbation gain spectra may take three possible forms. Under certain circumstances,it is even possible that there are two forms of gain spectra within certain range of perturbation frequency.
2004, 28(4): 431-433.
Abstract:
From 2001 to 2003,the research of growing seed and the experiment of cultivating Yunnan Sanjiao Fragrant Glutinous Rice was made by using laser irradiation and the electric field and magnetic field excitation. The research group discovered that a little rice had better variation character. The variation mechanism of rice seed growth is analyzed by Raman spectroscopy and quantum mechanics.
From 2001 to 2003,the research of growing seed and the experiment of cultivating Yunnan Sanjiao Fragrant Glutinous Rice was made by using laser irradiation and the electric field and magnetic field excitation. The research group discovered that a little rice had better variation character. The variation mechanism of rice seed growth is analyzed by Raman spectroscopy and quantum mechanics.
2004, 28(4): 434-437,448.
Abstract:
A new high power,short duration time XeCl laser is realized in order to prepare microstructure of quantum effect,depositing film,molecular beam epitaxy and analysis of output pulse profiles. It adopts the method of glow discharged,the calculation of dynamic equation,the analysis velocity reaction and density of XeCl laser,and UV preionization. In the addition,the parameters of the laser are also measured. The results are wavelength 308nm,the pulse duration time 18ns,the pulse energy 450mJ and the beam divergence angle 3mrad. It is shown that the proposed glow discharged is realized,the dynamic equation model of laser is correct,and the laser has high efficiency to produce the vapor plasma plume.It can be applied in the interaction between laser and material,material plasma study.
A new high power,short duration time XeCl laser is realized in order to prepare microstructure of quantum effect,depositing film,molecular beam epitaxy and analysis of output pulse profiles. It adopts the method of glow discharged,the calculation of dynamic equation,the analysis velocity reaction and density of XeCl laser,and UV preionization. In the addition,the parameters of the laser are also measured. The results are wavelength 308nm,the pulse duration time 18ns,the pulse energy 450mJ and the beam divergence angle 3mrad. It is shown that the proposed glow discharged is realized,the dynamic equation model of laser is correct,and the laser has high efficiency to produce the vapor plasma plume.It can be applied in the interaction between laser and material,material plasma study.
2004, 28(4): 438-441.
Abstract:
In this paper,the cheating-type laser interference,laser causing blind-interference,laser causing dizzy-interference and early-warning satellite of laser interference are discussed respectively.And the development of active laser interference technique is overviewed.The conclusion is that laser technique of source interference technique can apply to probing of photoelectricity,reconnoitre,fire-control,navigation and device of guidance.The strong laser interference of adoption to deal with the accurate guidance weapon will play important function in the defense, protecting naval force, large naval vessels and pointing military installation etc.
In this paper,the cheating-type laser interference,laser causing blind-interference,laser causing dizzy-interference and early-warning satellite of laser interference are discussed respectively.And the development of active laser interference technique is overviewed.The conclusion is that laser technique of source interference technique can apply to probing of photoelectricity,reconnoitre,fire-control,navigation and device of guidance.The strong laser interference of adoption to deal with the accurate guidance weapon will play important function in the defense, protecting naval force, large naval vessels and pointing military installation etc.
2004, 28(4): 442-444.
Abstract:
The construction and theory of position sensitive detection (PSD),the output equation at the presence of steady stray light are mainly introduced in this paper.In the same time,the methods of eliminating the steady stray light and the results of experiments are given.The experiment results show that the resolution of linear displacement can reach 2μm.
The construction and theory of position sensitive detection (PSD),the output equation at the presence of steady stray light are mainly introduced in this paper.In the same time,the methods of eliminating the steady stray light and the results of experiments are given.The experiment results show that the resolution of linear displacement can reach 2μm.
2004, 28(4): 445-448.
Abstract:
The double-linked gears in automobile gear-box have been welded with high power CO2 laser;several primary parameters affected welding quality have been analyzed;the welded products were analyzed and tested.The appearance of welding seam was perfect without hollow and welding bead.The ratio between depth and width exceeded 2:1;the hot influenced zone is narrow,the molten zone is compact without bug and the micro-hard reaches 450HV which is higher than raw materials. The gears didn't craze by 15kNm tortile test.
The double-linked gears in automobile gear-box have been welded with high power CO2 laser;several primary parameters affected welding quality have been analyzed;the welded products were analyzed and tested.The appearance of welding seam was perfect without hollow and welding bead.The ratio between depth and width exceeded 2:1;the hot influenced zone is narrow,the molten zone is compact without bug and the micro-hard reaches 450HV which is higher than raw materials. The gears didn't craze by 15kNm tortile test.
