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RSS1999 Vol. 23, No. 4
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1999, 23(4): 193-201.
[Abstract]
[PDF 806KB]
Abstract:
In the last three years, the enormous development has been made in the field of high energy laser weapon. The first generation of the practical weapon systems will come out soon. This article reviews American high energy laser weapon programs and recent developments. The significant progresses of various laser weapon technologies were reviewed and analyzed. Finally, we briefly describe the recent tests of the laser firing at a satellite.
In the last three years, the enormous development has been made in the field of high energy laser weapon. The first generation of the practical weapon systems will come out soon. This article reviews American high energy laser weapon programs and recent developments. The significant progresses of various laser weapon technologies were reviewed and analyzed. Finally, we briefly describe the recent tests of the laser firing at a satellite.
1999, 23(4): 202-203.
Abstract:
This paper introduced a novel mixed dye laser pumped by 6.0W CuBr laser.The mixed dye consists of three elements:Kiton Red,DCM and Nile Blue,and the ratio is 1:0.51:0.14.This laser can operate at the wavelength of 590nm～670nm with the line width 10nm.The output power above 1W and the conversion efficiency of 18% obtained.
This paper introduced a novel mixed dye laser pumped by 6.0W CuBr laser.The mixed dye consists of three elements:Kiton Red,DCM and Nile Blue,and the ratio is 1:0.51:0.14.This laser can operate at the wavelength of 590nm～670nm with the line width 10nm.The output power above 1W and the conversion efficiency of 18% obtained.
1999, 23(4): 205-209.
Abstract:
This paper presented the quasi stationary finite element model to describe the free surface situation of the melted pool by laser processing.It is show that Marangoni force and vapor pressure are two internal factors to influence the deformation of the free surface.When the temperature of the melted pool is lower than boiling point,the first one is the main effect,and the gravity will significantly influence the surface morphology.The main outer factor is the gas flow.The strength and the distribution of the gas flow.The strength and the distribution of the gas flow will too affect the surface morphology obviously.
This paper presented the quasi stationary finite element model to describe the free surface situation of the melted pool by laser processing.It is show that Marangoni force and vapor pressure are two internal factors to influence the deformation of the free surface.When the temperature of the melted pool is lower than boiling point,the first one is the main effect,and the gravity will significantly influence the surface morphology.The main outer factor is the gas flow.The strength and the distribution of the gas flow.The strength and the distribution of the gas flow will too affect the surface morphology obviously.
1999, 23(4): 209-212.
Abstract:
The return signals from airborne laser depth sounding have dynamic ranges that exceed the capabilities of the sequential measurement equipments.The study on gain controlling of photomutiplier tubes(PMT) GDB-333,GDB-49 and R1333 have been carried out.The results show that the signal dynamic range can be compressed to 2.5×104orders by controlling the electric potential of grid and eletromutiplier electrode.The method of changing PMT gain to detect signals from sea bottom is very compatible to airborne laser depth sounding.
The return signals from airborne laser depth sounding have dynamic ranges that exceed the capabilities of the sequential measurement equipments.The study on gain controlling of photomutiplier tubes(PMT) GDB-333,GDB-49 and R1333 have been carried out.The results show that the signal dynamic range can be compressed to 2.5×104orders by controlling the electric potential of grid and eletromutiplier electrode.The method of changing PMT gain to detect signals from sea bottom is very compatible to airborne laser depth sounding.
1999, 23(4): 213-215.
Abstract:
Dynamic angle measuring system has various utilities, and its technology is hard to realize. The dynamic angle measuring system using ring laser sensor (RLS) shows many advantages such as high accuracy, high speed, simple structure and easiness of operation, etc. We used output of RLS as the velocity feedback. The control system controls the table to rotate at a constant speed. Optical zero pointing sensor converts the reflecting light into electrical impulse to control the counter. Through many times of measurement and data processing in the computer, the repeated measurement accuracy reaches ±0.2 arcsec.
Dynamic angle measuring system has various utilities, and its technology is hard to realize. The dynamic angle measuring system using ring laser sensor (RLS) shows many advantages such as high accuracy, high speed, simple structure and easiness of operation, etc. We used output of RLS as the velocity feedback. The control system controls the table to rotate at a constant speed. Optical zero pointing sensor converts the reflecting light into electrical impulse to control the counter. Through many times of measurement and data processing in the computer, the repeated measurement accuracy reaches ±0.2 arcsec.
1999, 23(4): 216-219.
Abstract:
This paper introduces a new method for both producing and controlling the frequency difference of a dual frequency laser by using an electromagnetical force which is applied onto the window plate. In our experiments, we use a half-intracavity laser. The discharge tube's window plate with high anti-reflecting film is used as a stress birefringence element. The electromagnet applies a force along a diameter of the window plate. When the voltage of electromagnet is tuned, the force is adjusted too. So the frequency difference is produced and controlled. The frequency difference is detected by a photo-electric detector and countered by a frequency meter.
This paper introduces a new method for both producing and controlling the frequency difference of a dual frequency laser by using an electromagnetical force which is applied onto the window plate. In our experiments, we use a half-intracavity laser. The discharge tube's window plate with high anti-reflecting film is used as a stress birefringence element. The electromagnet applies a force along a diameter of the window plate. When the voltage of electromagnet is tuned, the force is adjusted too. So the frequency difference is produced and controlled. The frequency difference is detected by a photo-electric detector and countered by a frequency meter.
1999, 23(4): 220-224.
Abstract:
The self deflection process of bright photovoltaic spatial solitons in photovoltaic photorefractive media is investigated by taking into account diffusion effects.By using perturbation techniques,it is found that the center of the optical beam moves on a parabolic trajectory and,moreover,the central spatial frequency component shifts linearly with the propagation distance.Both the spatial deflection and the angular deviation are proportional to the product of two dimensionless quantities which are associated with the diffusion and the photovoltaic process,respectively.The photovoltaic solitons have a similar way to screening solitons in self bending process.
The self deflection process of bright photovoltaic spatial solitons in photovoltaic photorefractive media is investigated by taking into account diffusion effects.By using perturbation techniques,it is found that the center of the optical beam moves on a parabolic trajectory and,moreover,the central spatial frequency component shifts linearly with the propagation distance.Both the spatial deflection and the angular deviation are proportional to the product of two dimensionless quantities which are associated with the diffusion and the photovoltaic process,respectively.The photovoltaic solitons have a similar way to screening solitons in self bending process.
1999, 23(4): 224-227.
Abstract:
In order to study the discharge and break down characteristics of CO2 laser with distributing of gold rings ,a comparison experiment has been carried out with CO2 laser tubes one was typical, the other was improved by putting a series of gold rings in the discharge capillary .Two kinds of gases helium and neon have been used in the experiment. The results showed that both the break down voltage and the terminal voltage of the laser tube with gold rings are increasing significantly in comparison with the tube without gold rings.
In order to study the discharge and break down characteristics of CO2 laser with distributing of gold rings ,a comparison experiment has been carried out with CO2 laser tubes one was typical, the other was improved by putting a series of gold rings in the discharge capillary .Two kinds of gases helium and neon have been used in the experiment. The results showed that both the break down voltage and the terminal voltage of the laser tube with gold rings are increasing significantly in comparison with the tube without gold rings.
1999, 23(4): 228-231.
Abstract:
High-speed information transmission needs compatible high-speed information switching. It is a common sense that optical switching replaces electronic switching, and much effort has been taken in this kind of research. Optical fiber arrays are necessary E/O ports in an optical switching moduler. High precision test is required to ensure high accuracy of these optical fiber arrays. In this paper, a test method was presented. The optical fiber arrays were imaged with CCD, then the photograph was sent to PIP video digitizer board, measured and processed by computer software. This test method substituting the conventional mechanical one possesses advantages of high precision of 1μm or even less, and its convenience, which can meet the requirement of high accuracy.
High-speed information transmission needs compatible high-speed information switching. It is a common sense that optical switching replaces electronic switching, and much effort has been taken in this kind of research. Optical fiber arrays are necessary E/O ports in an optical switching moduler. High precision test is required to ensure high accuracy of these optical fiber arrays. In this paper, a test method was presented. The optical fiber arrays were imaged with CCD, then the photograph was sent to PIP video digitizer board, measured and processed by computer software. This test method substituting the conventional mechanical one possesses advantages of high precision of 1μm or even less, and its convenience, which can meet the requirement of high accuracy.
1999, 23(4): 231-233.
Abstract:
This paper reported the results of an experimental study for a Er3+-doped fiber ring laser.Using a semiconductor laser operating at 976nm as the pumping source,the maximum output power of Er3+-doped fiber ring laser was 0.94mW for 1.5581 nm wavelength,when a polarization insensitive ISO were used in the ring cavity.
This paper reported the results of an experimental study for a Er3+-doped fiber ring laser.Using a semiconductor laser operating at 976nm as the pumping source,the maximum output power of Er3+-doped fiber ring laser was 0.94mW for 1.5581 nm wavelength,when a polarization insensitive ISO were used in the ring cavity.
1999, 23(4): 234-237.
Abstract:
The paper proposed a method to forecast the output power of CO2 laser through the grey prediction arithmetic based on the theory of grey system in order to control the output power in advance, which is realized by C program with Yan Hua industry control computer to control confined discharge excited 2kW transversx flow CO2 laser.
The paper proposed a method to forecast the output power of CO2 laser through the grey prediction arithmetic based on the theory of grey system in order to control the output power in advance, which is realized by C program with Yan Hua industry control computer to control confined discharge excited 2kW transversx flow CO2 laser.
1999, 23(4): 238-241.
Abstract:
This paper deals with the laser welding of diamond core drills and the effect of technical parameters such as the focus position,beam power density and welding speed on the welding strength.The experiment results provide the better technical parameters to correct the practical welding procedure.
This paper deals with the laser welding of diamond core drills and the effect of technical parameters such as the focus position,beam power density and welding speed on the welding strength.The experiment results provide the better technical parameters to correct the practical welding procedure.
1999, 23(4): 241-243.
Abstract:
The Ti:Sapphire laser is an useful in laser spectroscope,laser chemistry,laser remote sensing,lidar,etc..In order to obtain high energy output,we have been successfully developed a double simmer flashlamp pumped Ti:Sapphire laser.The experimental results show that the higher simmer current can imporve the pumping rate,and the larger diameter laser rod has higher slope efficiency.In our system,the slope efficiency of the laser is 0.346% for 10 laser rod.
The Ti:Sapphire laser is an useful in laser spectroscope,laser chemistry,laser remote sensing,lidar,etc..In order to obtain high energy output,we have been successfully developed a double simmer flashlamp pumped Ti:Sapphire laser.The experimental results show that the higher simmer current can imporve the pumping rate,and the larger diameter laser rod has higher slope efficiency.In our system,the slope efficiency of the laser is 0.346% for 10 laser rod.
1999, 23(4): 244-247.
Abstract:
By analyzing the spherical-harmonic modes of irradiation nonuniformity, the general conditions are acquired for perfectly uniform irradiation of spherical targets for direct driven laser fusion from a finite number of laser beams. The results provide the theory for optimum designing practical multibeam irradiation systems and evaluating irradiation nonuniformity of spherical targets. Some typical examples that satisfy the conditions are presented.
By analyzing the spherical-harmonic modes of irradiation nonuniformity, the general conditions are acquired for perfectly uniform irradiation of spherical targets for direct driven laser fusion from a finite number of laser beams. The results provide the theory for optimum designing practical multibeam irradiation systems and evaluating irradiation nonuniformity of spherical targets. Some typical examples that satisfy the conditions are presented.
1999, 23(4): 248-251.
Abstract:
The diamond impregnated segments and steel core were welded by a high power laser in horizontal arrangement to achieve the very high bond strength.The theoretical and experimental study show that the beam alignment or beam shift will significantly effect the welding quality,such as the pore density in seams,microstructure,composition distribution of the seams.It is proved that the 0.1mm beam shift to steel substrate is the best to obtain the high bond strength.
The diamond impregnated segments and steel core were welded by a high power laser in horizontal arrangement to achieve the very high bond strength.The theoretical and experimental study show that the beam alignment or beam shift will significantly effect the welding quality,such as the pore density in seams,microstructure,composition distribution of the seams.It is proved that the 0.1mm beam shift to steel substrate is the best to obtain the high bond strength.
1999, 23(4): 252-254.
Abstract:
When laser beam goes through the solution with great amount of suspended particles,the light will be scattered.Collecting and detecting the scattred light intensity,the turbidity of the solution can be determined.Based on the principle,the mode JZ-Ⅳ turbidimeter has been developed.This turbidimeter consists of a He-Ne laser source,spectroscope,water tube photoelectric cell and a reference light battery.
When laser beam goes through the solution with great amount of suspended particles,the light will be scattered.Collecting and detecting the scattred light intensity,the turbidity of the solution can be determined.Based on the principle,the mode JZ-Ⅳ turbidimeter has been developed.This turbidimeter consists of a He-Ne laser source,spectroscope,water tube photoelectric cell and a reference light battery.
1999, 23(4): 255-257.
Abstract:
Adaptive optics are being used widely in laser material processing technology. The theory and a new application of adaptive optics are described in conventional laser cutting, thick sheet metal laser sawing and three-dimension laser welding.
Adaptive optics are being used widely in laser material processing technology. The theory and a new application of adaptive optics are described in conventional laser cutting, thick sheet metal laser sawing and three-dimension laser welding.
