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RSS2004 Vol. 28, No. 5
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2004, 28(5): 449-451.
[Abstract]
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Abstract:
A cyanine dye polymer film is made by spin-coated method,and the property of the film is studied with green light recording system with NA of 0.65 at room temperature.In the range of 420nm～590nm the film shows two strong absorption peaks,which means that this film can be used as optical storage material matching the recording system with the laser source of 532nm.A result of about 600nm recording line with 21% reflectivity contrast is obtained at 15mW laser power with the 1m/s recording velocity.
A cyanine dye polymer film is made by spin-coated method,and the property of the film is studied with green light recording system with NA of 0.65 at room temperature.In the range of 420nm～590nm the film shows two strong absorption peaks,which means that this film can be used as optical storage material matching the recording system with the laser source of 532nm.A result of about 600nm recording line with 21% reflectivity contrast is obtained at 15mW laser power with the 1m/s recording velocity.
2004, 28(5): 452-454.
Abstract:
Laser welding is widely used in practice,but it also has some disadvantages,such as porosity,low absorptivity for laser,and crack when high-carbon or high-alloy steels are welded.To overcome these shortcomings,a laser/high-frequency induction hybrid welding technology was presented,and 30CrMnSiA was welded by this method.Compared with laser welding,the martensite composition in the weld structure is less,the bainite composition is more,and the inclination of crack is less.The weld penetration and width are obviously increased by the hybrid welding.At the same time,the aided heat source of high-frequency induction neither enlarges the width of HAZ,nor worsens HAZ metallurgical structure.The experiment results have proved that the laser/high-frequency induction hybrid welding has the following advantages than laser welding: more excellent organization and performance of weld joint,lower inclining to bring porosity or crack,and higher welding efficiency.
Laser welding is widely used in practice,but it also has some disadvantages,such as porosity,low absorptivity for laser,and crack when high-carbon or high-alloy steels are welded.To overcome these shortcomings,a laser/high-frequency induction hybrid welding technology was presented,and 30CrMnSiA was welded by this method.Compared with laser welding,the martensite composition in the weld structure is less,the bainite composition is more,and the inclination of crack is less.The weld penetration and width are obviously increased by the hybrid welding.At the same time,the aided heat source of high-frequency induction neither enlarges the width of HAZ,nor worsens HAZ metallurgical structure.The experiment results have proved that the laser/high-frequency induction hybrid welding has the following advantages than laser welding: more excellent organization and performance of weld joint,lower inclining to bring porosity or crack,and higher welding efficiency.
2004, 28(5): 455-458.
Abstract:
With rapid prototyping introduced to the process of nano material,experiments on slective laser sintering of nano-alumina are carried out and effect of sintering parameters on the process is analyzed systematically.A reasonable selective laser sintering technique of nano-alumina which can be used to fabricate nano-structured parts with free shape is obtained and verified with a multi-layer sintering experiment.The component and the microstructure of the sintering production is tested.It is indicated that with the selective laser sintering technique obtained above,nano-alumina can be processed to manufacture three-dimension nano-structured parts with free shape,the crystal size of the production is almost kept the same as that of alumina powder.
With rapid prototyping introduced to the process of nano material,experiments on slective laser sintering of nano-alumina are carried out and effect of sintering parameters on the process is analyzed systematically.A reasonable selective laser sintering technique of nano-alumina which can be used to fabricate nano-structured parts with free shape is obtained and verified with a multi-layer sintering experiment.The component and the microstructure of the sintering production is tested.It is indicated that with the selective laser sintering technique obtained above,nano-alumina can be processed to manufacture three-dimension nano-structured parts with free shape,the crystal size of the production is almost kept the same as that of alumina powder.
2004, 28(5): 459-462.
Abstract:
The development of techniques of reflectivity measurements is reviewed and analyzed. Based on the measurement principles,the techniques can be divided into two types.One is single-reflectance,double-reflectance and multi-reflectance on the sample.The other is other measurement based on resonator's characteristics,such as optical cavity decay time,cavity ring-down spectroscopy,spherical cavity optical delay lines,the fineness of the resonator,and the loss compare between two active resonators.Their advantages and disadvantages,in particular,their measurement errors are discussed. Some current hot spots and future directions are analyzed.
The development of techniques of reflectivity measurements is reviewed and analyzed. Based on the measurement principles,the techniques can be divided into two types.One is single-reflectance,double-reflectance and multi-reflectance on the sample.The other is other measurement based on resonator's characteristics,such as optical cavity decay time,cavity ring-down spectroscopy,spherical cavity optical delay lines,the fineness of the resonator,and the loss compare between two active resonators.Their advantages and disadvantages,in particular,their measurement errors are discussed. Some current hot spots and future directions are analyzed.
2004, 28(5): 463-465,468.
Abstract:
Metal gradient thin films have many excellent properties and a wide use.The aim of our research is to find new method and new techniques of preparing metal gradient thin films.Al/Ag doping functional gradient thin films have been successful synthesized on Si (100) substrate by using scanning pulsed excimer laser ablation technique.The structure of Al/Ag thin films deposited by pulsed laser deposition(PLD) is analyzed by scanning electron microscope(SEM),X-ray photoelectron spectroscopy(XPS).The experimental results illustrate that applying appropriate laser parameter and assistant discharge can synthesize the Al/Ag thin films with approximate ratio 5:1 at the 300℃.This experimental method indicates that it is feasible to deposit functional gradient metal thin films by means of the interaction between pulsed laser and metal doping target.
Metal gradient thin films have many excellent properties and a wide use.The aim of our research is to find new method and new techniques of preparing metal gradient thin films.Al/Ag doping functional gradient thin films have been successful synthesized on Si (100) substrate by using scanning pulsed excimer laser ablation technique.The structure of Al/Ag thin films deposited by pulsed laser deposition(PLD) is analyzed by scanning electron microscope(SEM),X-ray photoelectron spectroscopy(XPS).The experimental results illustrate that applying appropriate laser parameter and assistant discharge can synthesize the Al/Ag thin films with approximate ratio 5:1 at the 300℃.This experimental method indicates that it is feasible to deposit functional gradient metal thin films by means of the interaction between pulsed laser and metal doping target.
2004, 28(5): 466-468.
Abstract:
The frequency tuning of LD-pumped non-planar ring Nd:YAG resonator laser is studied.The output power of the 1319nm single frequency laser is tuned broadly in 14GHz by temperature control.Further more,the main cause of single-frequency laser's intensity noise is studied.The intensity noise is measured and the result for an active feedback loop that suppresses the relaxation oscillation noise is presented.The intensity noise is suppressed 30dB at the central frequency of relaxation oscillation,measurement precision is improved.
The frequency tuning of LD-pumped non-planar ring Nd:YAG resonator laser is studied.The output power of the 1319nm single frequency laser is tuned broadly in 14GHz by temperature control.Further more,the main cause of single-frequency laser's intensity noise is studied.The intensity noise is measured and the result for an active feedback loop that suppresses the relaxation oscillation noise is presented.The intensity noise is suppressed 30dB at the central frequency of relaxation oscillation,measurement precision is improved.
2004, 28(5): 469-471,475.
Abstract:
In this paper,the development of XGⅡ high power solid-state laser facility and the physical experimental research are briefly introduced.A system with two-probe laser beams has been developed based on XGⅡ high power solid-state laser facility which is used for laser plasma diagnostic experiments.The design optimization method of energy system and new research progress of concentrate control system of the laser facility has also been explained here,and the methods and results obtained in this paper are applicable to the design of high power solid-state laser system.
In this paper,the development of XGⅡ high power solid-state laser facility and the physical experimental research are briefly introduced.A system with two-probe laser beams has been developed based on XGⅡ high power solid-state laser facility which is used for laser plasma diagnostic experiments.The design optimization method of energy system and new research progress of concentrate control system of the laser facility has also been explained here,and the methods and results obtained in this paper are applicable to the design of high power solid-state laser system.
2004, 28(5): 472-475.
Abstract:
The roll surface experiences severe thermal circulation during the laser strengthening.Due to the concentration of the temperature field,the stress on the roll surface changes dynamically,and the transient distribution within the laser spot is mainly compressive.Furthermore,as the change of the specific volume of the micro-structure,the residual stress distribution after the laser treatment is very complicated.As a result,it is very difficult to measure the stress distribution experimentally.So it is a reasonable choice to simulate the distribution with the numerical method.
The roll surface experiences severe thermal circulation during the laser strengthening.Due to the concentration of the temperature field,the stress on the roll surface changes dynamically,and the transient distribution within the laser spot is mainly compressive.Furthermore,as the change of the specific volume of the micro-structure,the residual stress distribution after the laser treatment is very complicated.As a result,it is very difficult to measure the stress distribution experimentally.So it is a reasonable choice to simulate the distribution with the numerical method.
2004, 28(5): 476-479.
Abstract:
A numerical model for the discharge processes of a UV-preionized transversely excited atmospheric pressure (TEA) CO2 laser is presented,in which the discharge circuit and the discharge area are considered in detail,and the temporal evolution of discharge voltage,current and electron density are given.Comparisons of the simulation results with the related experimental results are presented together with discussions of the factors affecting the stability of gas discharge in the laser.
A numerical model for the discharge processes of a UV-preionized transversely excited atmospheric pressure (TEA) CO2 laser is presented,in which the discharge circuit and the discharge area are considered in detail,and the temporal evolution of discharge voltage,current and electron density are given.Comparisons of the simulation results with the related experimental results are presented together with discussions of the factors affecting the stability of gas discharge in the laser.
2004, 28(5): 480-481,542.
Abstract:
A large volume spark preionized pulsed HF laser is reported.Stable diffuse discharge occurs in an active volume 4cm×5cm×80cm of SF6 and C2H6 hybrid gas.Under the condition of gas pressure 12.6kPa and charge voltage 45kV,the laser gives laser output energy up to 3J with a pulsed peak power 18MW.
A large volume spark preionized pulsed HF laser is reported.Stable diffuse discharge occurs in an active volume 4cm×5cm×80cm of SF6 and C2H6 hybrid gas.Under the condition of gas pressure 12.6kPa and charge voltage 45kV,the laser gives laser output energy up to 3J with a pulsed peak power 18MW.
2004, 28(5): 482-484,538.
Abstract:
By utilizing the theories of Fresnel diffraction and amplitude holography,the effects of configuration parameters on the numerical reconstruction of off-axis digital holographic recording system are analyzed and the corresponding experiment is operated.The results of theoretical analysis and experiment show: if the sizes of recorded object and CCD are fixed,the distance between the recorded object and CCD has a direct impact on the resolution of the system and the separation of the three images in reconstruction plane.If the premise of separation status of the reconstructed images is satisfied,shortening the distance between the object and CCD redounds to improving the resolution of reconstructed image.
By utilizing the theories of Fresnel diffraction and amplitude holography,the effects of configuration parameters on the numerical reconstruction of off-axis digital holographic recording system are analyzed and the corresponding experiment is operated.The results of theoretical analysis and experiment show: if the sizes of recorded object and CCD are fixed,the distance between the recorded object and CCD has a direct impact on the resolution of the system and the separation of the three images in reconstruction plane.If the premise of separation status of the reconstructed images is satisfied,shortening the distance between the object and CCD redounds to improving the resolution of reconstructed image.
2004, 28(5): 485-487,553.
Abstract:
Several parameters that affect the output pulse characteristics of electro-optically(E-O) cavity-dumped RF waveguide laser have been discussed.By changing the rising time of high voltage pulse in CdTe crystal and reflectivity of Brewster window,the varieties of output pulse width and peak power of cavity-dumped laser are theoretically studied.By changing these parameters,in a home-made CdTe E-O cavity-dumped double-channel RF excited CO2 waveguide laser,which might be used as a light sources in a heterodyne imaging lidar system,we have obtained the cavity dumped pulses width at FWHM from 20ns to 30ns.
Several parameters that affect the output pulse characteristics of electro-optically(E-O) cavity-dumped RF waveguide laser have been discussed.By changing the rising time of high voltage pulse in CdTe crystal and reflectivity of Brewster window,the varieties of output pulse width and peak power of cavity-dumped laser are theoretically studied.By changing these parameters,in a home-made CdTe E-O cavity-dumped double-channel RF excited CO2 waveguide laser,which might be used as a light sources in a heterodyne imaging lidar system,we have obtained the cavity dumped pulses width at FWHM from 20ns to 30ns.
2004, 28(5): 488-490,502.
Abstract:
Optical characteristics of the Nd:YAG polycrystalline ceramic with Nd concentration of 1%,such as absorption spectrum,fluorescence spectra,transmission spectrum and fluorescence life are measured,which are compared with those of Nd:YAG single crystal.Results demonstrate Nd:YAG polycrystalline transparent ceramic to be a potential laser medium.
Optical characteristics of the Nd:YAG polycrystalline ceramic with Nd concentration of 1%,such as absorption spectrum,fluorescence spectra,transmission spectrum and fluorescence life are measured,which are compared with those of Nd:YAG single crystal.Results demonstrate Nd:YAG polycrystalline transparent ceramic to be a potential laser medium.
2004, 28(5): 491-493.
Abstract:
The study on detecting,identifying and controlling the biological molecules in water is profound and significant project.We used the means of the resonance Raman spectra in the liquid-core optical fiber,and the intensity of the Raman spectra was enhanced 109 times.β-carotene was dissolved in organic solution(pyridine and water),poured into a number of hollow-core capillary made up of liquid-core optical fiber.The laser wavelength is 514.5nm.The laser power is 30mW.By this means we obtained the resonance Raman spectra of β-carotene with the concentration of 10-7mol/L～10-9 mol/L.This means provided an experiment technique for trace analysis of biological molecules in water.
The study on detecting,identifying and controlling the biological molecules in water is profound and significant project.We used the means of the resonance Raman spectra in the liquid-core optical fiber,and the intensity of the Raman spectra was enhanced 109 times.β-carotene was dissolved in organic solution(pyridine and water),poured into a number of hollow-core capillary made up of liquid-core optical fiber.The laser wavelength is 514.5nm.The laser power is 30mW.By this means we obtained the resonance Raman spectra of β-carotene with the concentration of 10-7mol/L～10-9 mol/L.This means provided an experiment technique for trace analysis of biological molecules in water.
2004, 28(5): 494-497.
Abstract:
Using corn as the experiment material,in this experiment 18mW/mm2 CO2 laser radiates corn grain so as to test the effect radiation on the corn seed development.The results show that this treatment produces positive effect on corn grain germination,its further development with in 15d after germination and physiological metabolism.30s treatment has no obvious effect.60s and 90s treatment can have a significant effect on the development of corn seedling.
Using corn as the experiment material,in this experiment 18mW/mm2 CO2 laser radiates corn grain so as to test the effect radiation on the corn seed development.The results show that this treatment produces positive effect on corn grain germination,its further development with in 15d after germination and physiological metabolism.30s treatment has no obvious effect.60s and 90s treatment can have a significant effect on the development of corn seedling.
2004, 28(5): 498-502.
Abstract:
The present research situation of Brillouin fiber-optic ring lasers is introduced. The Brillouin fiber-optic lasers have advantages of narrow line width,stable frequency,directional sensitivity of the SBS gain,etc. Brillouin fiber-optic gyroscope as the principal application is discussed in detail.
The present research situation of Brillouin fiber-optic ring lasers is introduced. The Brillouin fiber-optic lasers have advantages of narrow line width,stable frequency,directional sensitivity of the SBS gain,etc. Brillouin fiber-optic gyroscope as the principal application is discussed in detail.
2004, 28(5): 503-505.
Abstract:
For direct detection,long-range CO2 differential absorption lidar (DIAL) system,two factors which have effects on measurement sensitivity:atmospheric turbulence and laser speckle are analyzed.Numerical calculation results of the dependent relationship between measurement sensitivity and atmospheric turbulence and laser speckle are obtained.These results show that when the height is smaller than 350m,measurement sensitivity can be efficiently improved by increasing the height of equipment above ground;when the height is bigger than 350m,measurement sensitivity can be efficiently improved by changing system parameters.
For direct detection,long-range CO2 differential absorption lidar (DIAL) system,two factors which have effects on measurement sensitivity:atmospheric turbulence and laser speckle are analyzed.Numerical calculation results of the dependent relationship between measurement sensitivity and atmospheric turbulence and laser speckle are obtained.These results show that when the height is smaller than 350m,measurement sensitivity can be efficiently improved by increasing the height of equipment above ground;when the height is bigger than 350m,measurement sensitivity can be efficiently improved by changing system parameters.
Recent research and development of fiber-optic grating writing technologies for sensing applications
2004, 28(5): 506-509,520.
Abstract:
To overcome the adverse circumstance of the fiber-optic gratings designed for communication used in sensing applications,based on the summarization of the general demands and characteristics of the sensing fiber-optic gratings,the writing technologies on several sensing fiber Bragg gratings such as those with good resistance property of high temperature,excellent enhancing/weakening sensitivity and high mechanical strength are described concretely.Then the UV-exposing,mechanical-distorting and IR-laser point-by-point inscripting methods for sensing long period fiber gratings are presented respectively.At last the trend of writing technologies for the sensing fiber-optic gratings is forecasted.
To overcome the adverse circumstance of the fiber-optic gratings designed for communication used in sensing applications,based on the summarization of the general demands and characteristics of the sensing fiber-optic gratings,the writing technologies on several sensing fiber Bragg gratings such as those with good resistance property of high temperature,excellent enhancing/weakening sensitivity and high mechanical strength are described concretely.Then the UV-exposing,mechanical-distorting and IR-laser point-by-point inscripting methods for sensing long period fiber gratings are presented respectively.At last the trend of writing technologies for the sensing fiber-optic gratings is forecasted.
2004, 28(5): 510-513.
Abstract:
In high power CO2 laser the infrared material output-coupler window inevitable absorbing resonant laser energy will produce non-uniform temperature field distribution,and also cause output coupler window to generate thermal distortion,which is called the output-coupler window thermal effect.Thermal effect would change resonant Q-factor,and influence laser stability and output beam quality.So accurate temperature field and thermal distortion field analysis is the key to resolve these problems.In this article semi-analytical solution is introduced to study output coupler window non-uniform temperature field distribution and thermal distortion field distribution under the CO2 laser operated at stable TEM00 mode.Fortunately the research method and obtained results have universality,which can be applied to analyze temperature field and thermal distortion field with axial symmetry thermal models.
In high power CO2 laser the infrared material output-coupler window inevitable absorbing resonant laser energy will produce non-uniform temperature field distribution,and also cause output coupler window to generate thermal distortion,which is called the output-coupler window thermal effect.Thermal effect would change resonant Q-factor,and influence laser stability and output beam quality.So accurate temperature field and thermal distortion field analysis is the key to resolve these problems.In this article semi-analytical solution is introduced to study output coupler window non-uniform temperature field distribution and thermal distortion field distribution under the CO2 laser operated at stable TEM00 mode.Fortunately the research method and obtained results have universality,which can be applied to analyze temperature field and thermal distortion field with axial symmetry thermal models.
2004, 28(5): 514-517.
Abstract:
By using a four-dimensional simulation code,a detailed numerical study of the influence of thermal effects and aberrations in a beam control system on the beam quality is made. The Strehl ratio,β,astigmatism parameters and power in the bucket (PIB) are chosen as criteria for characterizing the beam quality in the far field.It is shown that the defocus,astigmatism and thermal effects result in the distortion of intensity distribution and reduction of the focusability in the far field,thus degrade the beam quality.
By using a four-dimensional simulation code,a detailed numerical study of the influence of thermal effects and aberrations in a beam control system on the beam quality is made. The Strehl ratio,β,astigmatism parameters and power in the bucket (PIB) are chosen as criteria for characterizing the beam quality in the far field.It is shown that the defocus,astigmatism and thermal effects result in the distortion of intensity distribution and reduction of the focusability in the far field,thus degrade the beam quality.
2004, 28(5): 518-520.
Abstract:
The paper gives a theoretical method of applying Brillouin scattering principle to detect spatial object.The properties of Brillouin scattering of atmosphere,metal coat of spatial object and concealed material are calculated,analyzed and compared.The result shows that the discrepancy of the frequency shifting of atmosphere,metal coat of spatial object and concealed material is at least more than 10 times,thus it is applicable to use Brillouin scattering to detect spatial objects.The article not only calculates the frequency shifting,but also studies the technique for detection,and adopts a technique of using narrow-band quantum optical filter system to distinguish the scattered light accurately.
The paper gives a theoretical method of applying Brillouin scattering principle to detect spatial object.The properties of Brillouin scattering of atmosphere,metal coat of spatial object and concealed material are calculated,analyzed and compared.The result shows that the discrepancy of the frequency shifting of atmosphere,metal coat of spatial object and concealed material is at least more than 10 times,thus it is applicable to use Brillouin scattering to detect spatial objects.The article not only calculates the frequency shifting,but also studies the technique for detection,and adopts a technique of using narrow-band quantum optical filter system to distinguish the scattered light accurately.
2004, 28(5): 521-523,530.
Abstract:
In the designed auto adaptive cruise control system,infrared laser ranging measures the distance between the main and the objective vehicles.The wavelength of the laser and the precision of the distance are very important to the reliability of the system.The factors affecting the accuracy of laser ranging are analyzed.Then the digital interpolating time counting method has been proposed to produce the high precision of distance measuring.Considering factors such as attenuation,reflectivity,system cost and eye safety,a 1.6 μm infrared laser wavelength is suggested as optimum.And the laser driving circuits and the detect-amplifying circuits are introduced.
In the designed auto adaptive cruise control system,infrared laser ranging measures the distance between the main and the objective vehicles.The wavelength of the laser and the precision of the distance are very important to the reliability of the system.The factors affecting the accuracy of laser ranging are analyzed.Then the digital interpolating time counting method has been proposed to produce the high precision of distance measuring.Considering factors such as attenuation,reflectivity,system cost and eye safety,a 1.6 μm infrared laser wavelength is suggested as optimum.And the laser driving circuits and the detect-amplifying circuits are introduced.
2004, 28(5): 524-526,560.
Abstract:
In this paper,a laser digitizing and machining system is studied and designed.This system realizes the non-contact measurement in NC copying machine.It can not only relax restriction on copying model material and stiffness,but also effectively solve the interference of contact detector with large curvature surface.At the same time,the system improves the ability that NC copying machine processes the complicated model.
In this paper,a laser digitizing and machining system is studied and designed.This system realizes the non-contact measurement in NC copying machine.It can not only relax restriction on copying model material and stiffness,but also effectively solve the interference of contact detector with large curvature surface.At the same time,the system improves the ability that NC copying machine processes the complicated model.
2004, 28(5): 527-530.
Abstract:
The analogical signal processor of the laser ranger can not make use of the interrelated information between pulses. Therefore,checking the target is limited. The digital signal processor of the laser ranger can make use of the interrelated information between pulses. The target matching and tracking algorithm makes use of the interrelated information,decreases the threshold and increases the range. This paper studies the false alarming rate and detecting probability and proves that this algorithm is effective.
The analogical signal processor of the laser ranger can not make use of the interrelated information between pulses. Therefore,checking the target is limited. The digital signal processor of the laser ranger can make use of the interrelated information between pulses. The target matching and tracking algorithm makes use of the interrelated information,decreases the threshold and increases the range. This paper studies the false alarming rate and detecting probability and proves that this algorithm is effective.
2004, 28(5): 531-533.
Abstract:
A precision measuring method and device for large size work-piece is presented in the paper.The frequency-stabilized double longitudinal modes He-Ne laser with thermoregulation is used as light source,which has high stability of frequency difference(less than 1×10-7 in the open air) and good anti-disturbance performance that has been proved by theory and experiments.Its beat frequency is about 750MHz and beat wavelength 400mm.The node is used as sampling flag and the beat-wave fringe fraction is measured with double frequency interferometer combined by optical components.The experiments indicate that the accuracy of determining nodes is less than 0.05mm,the resolution for measuring fringe fraction is 0.08μm,the accuracy of the device is ±50μm+1.5×10-6·L(L is the measured distance,unit m)in the range of 20m length.
A precision measuring method and device for large size work-piece is presented in the paper.The frequency-stabilized double longitudinal modes He-Ne laser with thermoregulation is used as light source,which has high stability of frequency difference(less than 1×10-7 in the open air) and good anti-disturbance performance that has been proved by theory and experiments.Its beat frequency is about 750MHz and beat wavelength 400mm.The node is used as sampling flag and the beat-wave fringe fraction is measured with double frequency interferometer combined by optical components.The experiments indicate that the accuracy of determining nodes is less than 0.05mm,the resolution for measuring fringe fraction is 0.08μm,the accuracy of the device is ±50μm+1.5×10-6·L(L is the measured distance,unit m)in the range of 20m length.
2004, 28(5): 534-538.
Abstract:
The basic principle of a new and innovative concept high power solid-state heat capacity laser is introduced.The development and the current status in the area of solid-state heat capacity lasers are also described.The key technique is analyzed.The future prospect is discussed.
The basic principle of a new and innovative concept high power solid-state heat capacity laser is introduced.The development and the current status in the area of solid-state heat capacity lasers are also described.The key technique is analyzed.The future prospect is discussed.
2004, 28(5): 539-542.
Abstract:
The types of shadow noise in interferogram are accounted for and the methods of shadow correction are introduced briefly.This paper puts forward the minimal value method in each template block and the manual criterion method to correct additive noise and the Gaussian blur method to correct multiplicative noise in the spatial field.The methods are analyzed theoretically and applied to process the interferogram to be proved to be feasible and get the satisfied result.
The types of shadow noise in interferogram are accounted for and the methods of shadow correction are introduced briefly.This paper puts forward the minimal value method in each template block and the manual criterion method to correct additive noise and the Gaussian blur method to correct multiplicative noise in the spatial field.The methods are analyzed theoretically and applied to process the interferogram to be proved to be feasible and get the satisfied result.
2004, 28(5): 543-546.
Abstract:
The radiuses of equivalent Gaussian beam of different kinds of lasers are studied by using 86.5% loop enclosing power method.Combining with the experiments of heat treatment,heat action results are compared by using fast calculation math tool of heat action of arbitrarily distributed beam. The question of beam parameters expression in laser heat treatment is also discussed.
The radiuses of equivalent Gaussian beam of different kinds of lasers are studied by using 86.5% loop enclosing power method.Combining with the experiments of heat treatment,heat action results are compared by using fast calculation math tool of heat action of arbitrarily distributed beam. The question of beam parameters expression in laser heat treatment is also discussed.
2004, 28(5): 547-549.
Abstract:
A new monitor and control method for AR coating in mass production of traveling wave semiconductor optical amplifier(SOA) has been presented. With simplicity in system and operation, this technology can be applied to coating equipment made inland. Approximately as low as 10-4 of residual reflectivity in mass production with uniformity and repetition has been demonstrated.
A new monitor and control method for AR coating in mass production of traveling wave semiconductor optical amplifier(SOA) has been presented. With simplicity in system and operation, this technology can be applied to coating equipment made inland. Approximately as low as 10-4 of residual reflectivity in mass production with uniformity and repetition has been demonstrated.
2004, 28(5): 550-553.
Abstract:
Stereovision is one of the most widely used techniques as a powerful passive optical sensing method.The stereo matching is a key point of such technique.However,the conventional matching method is rather inefficient to measure continuous and characterless surface,which may lead to severe matching mistakes.So an aided digital speckle projection is proposed in such environment.The dense disparity map is achieved using the mean normalized cross correlation in our experiment.
Stereovision is one of the most widely used techniques as a powerful passive optical sensing method.The stereo matching is a key point of such technique.However,the conventional matching method is rather inefficient to measure continuous and characterless surface,which may lead to severe matching mistakes.So an aided digital speckle projection is proposed in such environment.The dense disparity map is achieved using the mean normalized cross correlation in our experiment.
2004, 28(5): 554-556.
Abstract:
Numerical solutions to the soliton nonliner Schrodinger (NLS) equation of higher-order dispersion effect find the third-order dispersion effect causing the soliton pulse seat to oscillate on a single side and the fourth-order effect causing it to oscillate on both sides,which result in the neighboring optical pulses overlapping and the shapes of the optical pulses distorting.The secondary pulses are evoked between the pair of optical soliton,therefore,cause systematic error code.We suggest that the third-order dispersion should be compensated on purpose in order to reduce systematic error code.
Numerical solutions to the soliton nonliner Schrodinger (NLS) equation of higher-order dispersion effect find the third-order dispersion effect causing the soliton pulse seat to oscillate on a single side and the fourth-order effect causing it to oscillate on both sides,which result in the neighboring optical pulses overlapping and the shapes of the optical pulses distorting.The secondary pulses are evoked between the pair of optical soliton,therefore,cause systematic error code.We suggest that the third-order dispersion should be compensated on purpose in order to reduce systematic error code.
2004, 28(5): 557-560.
Abstract:
The comparison of the two mathematical-physical models describing flat-topped beams,i.e.,the flattened Gaussian beam (FGB) and flat-topped multi-Gaussian beam (FMGB) is made.Numerical results and physical analysis are given.It is found that both FMGB and FGB having the same M2 factor exhibit a similar transversal intensity distribution at a position of the equal generalized Fresnel number,whenever their waist width is equal or not.This conclusion is useful for practical applications.
The comparison of the two mathematical-physical models describing flat-topped beams,i.e.,the flattened Gaussian beam (FGB) and flat-topped multi-Gaussian beam (FMGB) is made.Numerical results and physical analysis are given.It is found that both FMGB and FGB having the same M2 factor exhibit a similar transversal intensity distribution at a position of the equal generalized Fresnel number,whenever their waist width is equal or not.This conclusion is useful for practical applications.
