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RSS2000 Vol. 24, No. 5
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2000, 24(5): 259-262.
Abstract:
The reverse absorption and optical limiting properties of tetrabromo-2,3-naphthalocyanine copper(Ⅱ) are investigated The effects of heavy atoms and bromine atoms upon the opto-physical properties are analyzed by comparing the experimental results of bromo-substituted and unsubstituted naphthalocyanine copper with an excited state absorption model The optical limiting effect of tetrabromo-2,3-naphthalocyanine copper(Ⅱ) is better than that of naphthalocyanine copper(Ⅱ) and fullerene.
The reverse absorption and optical limiting properties of tetrabromo-2,3-naphthalocyanine copper(Ⅱ) are investigated The effects of heavy atoms and bromine atoms upon the opto-physical properties are analyzed by comparing the experimental results of bromo-substituted and unsubstituted naphthalocyanine copper with an excited state absorption model The optical limiting effect of tetrabromo-2,3-naphthalocyanine copper(Ⅱ) is better than that of naphthalocyanine copper(Ⅱ) and fullerene.
2000, 24(5): 262-264.
Abstract:
An eye safe 1.57μm OPO laser rangefinder has been developed.Outdoor ranging tests indicate that the range distance is up to 7050m under ～10km visibility,with range accuracy±5m,PRF 20Hz.The rangefinder uses a compact KTP 1.5 7μm single resonator OPO pumped by a water cooling flash lamp pumped EO switched (Ce,Nd):YAG laser.The output of the laser rangefinder is 12mJ/pulse and the pulse width is about 6ns.The receiver uses an InGaAs PIN detector.
An eye safe 1.57μm OPO laser rangefinder has been developed.Outdoor ranging tests indicate that the range distance is up to 7050m under ～10km visibility,with range accuracy±5m,PRF 20Hz.The rangefinder uses a compact KTP 1.5 7μm single resonator OPO pumped by a water cooling flash lamp pumped EO switched (Ce,Nd):YAG laser.The output of the laser rangefinder is 12mJ/pulse and the pulse width is about 6ns.The receiver uses an InGaAs PIN detector.
Optimum schemes of dispersion compensation transmission systems using dispersion compensation fibers
2000, 24(5): 265-269.
Abstract:
The optimum schemes of dispersion compensation transmission systems using dispersion compensation fibers are studied in this paper. It is found that the hybrid compensation scheme can reduce the influences of the fiber nonlinearity and increase the transmission distance greatly. In addition, the transmission performances of NRZ and RZ code are compared.
The optimum schemes of dispersion compensation transmission systems using dispersion compensation fibers are studied in this paper. It is found that the hybrid compensation scheme can reduce the influences of the fiber nonlinearity and increase the transmission distance greatly. In addition, the transmission performances of NRZ and RZ code are compared.
2000, 24(5): 270-272.
Abstract:
In this paper,type Ⅰ/type Ⅱ angle detuning and type Ⅱ/type Ⅱ po larization mismatch third harmonic generation scheme consisting of two doublers and two triplers are used.The scheme has been used to drive ignition targets,with high tripling efficiency for shaping pulse.The effects of depolarized fundamental radiation on the tripling efficiency and how to increase the tripling efficiency are discussed by means of modeling computation.The results give reference to engineering design.
In this paper,type Ⅰ/type Ⅱ angle detuning and type Ⅱ/type Ⅱ po larization mismatch third harmonic generation scheme consisting of two doublers and two triplers are used.The scheme has been used to drive ignition targets,with high tripling efficiency for shaping pulse.The effects of depolarized fundamental radiation on the tripling efficiency and how to increase the tripling efficiency are discussed by means of modeling computation.The results give reference to engineering design.
2000, 24(5): 273-276.
Abstract:
In experiment and theory,the studies on the third continuum of argon in the word are introduced In experiment,with different pumping ways,the shape of fluorescence and time resolved spectra are measured Up to now the small signal gain of this continuum has been reported In theory,with the calculations of spectrum and kinetics,the origin of the continuum is studied There are two main hypothesis that the continuum can be emitted by the transition of Ar22+ and Ar2+ ionic excimers Because either of the two hypothesis can only interprete a part of experimental results,there are no identical conclusions about the origin of the third continuum.
In experiment and theory,the studies on the third continuum of argon in the word are introduced In experiment,with different pumping ways,the shape of fluorescence and time resolved spectra are measured Up to now the small signal gain of this continuum has been reported In theory,with the calculations of spectrum and kinetics,the origin of the continuum is studied There are two main hypothesis that the continuum can be emitted by the transition of Ar22+ and Ar2+ ionic excimers Because either of the two hypothesis can only interprete a part of experimental results,there are no identical conclusions about the origin of the third continuum.
2000, 24(5): 277-280.
Abstract:
A H2/air premixed flat flame burner as calibra tion source for CARS temperature and species concentration measurements was esta blished. Temperatures for various stoichiometries along longitude and transv erse have been systematically measured by N2 CARS. The results indicate that difference between measurement temperature and the corresponding theoretical value is about 3.4 percent. Whereas temperature is nearly invariant beyond 1 mm above the burner surface, the associated error is around 1.8 percent.
A H2/air premixed flat flame burner as calibra tion source for CARS temperature and species concentration measurements was esta blished. Temperatures for various stoichiometries along longitude and transv erse have been systematically measured by N2 CARS. The results indicate that difference between measurement temperature and the corresponding theoretical value is about 3.4 percent. Whereas temperature is nearly invariant beyond 1 mm above the burner surface, the associated error is around 1.8 percent.
2000, 24(5): 281-284.
Abstract:
This paper deals with the laser cutting parameters for Al-silica te short fibre reinforced aluminum matrix composite and the heat-affecting zone(HAZ) of laser interaction.The results show that under the condition of 2kW CO2 laser and cutting velocity of 1～8m/min,penetrated and narrow cutting kerf and small HAZ had been gotten on composite samples whose thickness is from 1 to 4.2mm. Because of the effect of heat conduction,the microstructure of HAZ of laser cutting samples is different from that of the original composite and subsequently precipitated a silicon rich phase by the melted Al-silicate fibres.
This paper deals with the laser cutting parameters for Al-silica te short fibre reinforced aluminum matrix composite and the heat-affecting zone(HAZ) of laser interaction.The results show that under the condition of 2kW CO2 laser and cutting velocity of 1～8m/min,penetrated and narrow cutting kerf and small HAZ had been gotten on composite samples whose thickness is from 1 to 4.2mm. Because of the effect of heat conduction,the microstructure of HAZ of laser cutting samples is different from that of the original composite and subsequently precipitated a silicon rich phase by the melted Al-silicate fibres.
2000, 24(5): 285-288.
Abstract:
Investigations have been made to determine relations between the oscillation frequency ν of the ECLD and threshold carrier density N (orgain coefficient g),refractive indexn as well as mode frequency Nν of the diode. Afterwards,the perturbation method has been adopted to check the stability of the state represented by the points on the N-ν curve. The results indicate that two segments of vital importance for the formation of the loop,which were formerly misjudged as representing non stable states,represent stable state. Therefore,the hysteresis loop on the N-ν curve can be accomplished.
Investigations have been made to determine relations between the oscillation frequency ν of the ECLD and threshold carrier density N (orgain coefficient g),refractive indexn as well as mode frequency Nν of the diode. Afterwards,the perturbation method has been adopted to check the stability of the state represented by the points on the N-ν curve. The results indicate that two segments of vital importance for the formation of the loop,which were formerly misjudged as representing non stable states,represent stable state. Therefore,the hysteresis loop on the N-ν curve can be accomplished.
2000, 24(5): 289-292.
Abstract:
In recently years,the laser holography techniques have achieved great developments in the anti-counterfeiting fields. But there are several questions in anti-counterfeiting quality of holograms. In this paper,we analyse some hologram counterfeiting methods and present relavant security and protection measures for counterfeiting in laser holography anti counterfeiting applications,which can make progresses for laser holography anti-counterfeiting technique and remain laser holography industries invincible position.
In recently years,the laser holography techniques have achieved great developments in the anti-counterfeiting fields. But there are several questions in anti-counterfeiting quality of holograms. In this paper,we analyse some hologram counterfeiting methods and present relavant security and protection measures for counterfeiting in laser holography anti counterfeiting applications,which can make progresses for laser holography anti-counterfeiting technique and remain laser holography industries invincible position.
2000, 24(5): 292-296.
Abstract:
The temperature fluctuation of copper surface,which was in a the rmal equilibrium state under the irradia ted condition with a CW CO2 laser,was carefully measured.And the maximum range of the temperature fluctuation was no relation to laser irradiation time.So the temperature fluctuation of the copper su rface showed considerably the laser power stability of 5kW CW transverse flow CO2 laser.The result was useful to control the power stability of a CO2 laser.
The temperature fluctuation of copper surface,which was in a the rmal equilibrium state under the irradia ted condition with a CW CO2 laser,was carefully measured.And the maximum range of the temperature fluctuation was no relation to laser irradiation time.So the temperature fluctuation of the copper su rface showed considerably the laser power stability of 5kW CW transverse flow CO2 laser.The result was useful to control the power stability of a CO2 laser.
2000, 24(5): 297-300.
Abstract:
According to the analysis of the measurement error of particle size analyzer,we found that the main reas on of mistake judgement was multi-peak scattering spectrum.Several factors could produce the multi-peak scattering spectrum,such as optical unsymmetry of particles,shape of the particles,beam profile un-uniformity.This paper proposed a inte grating judgement method to avoid the mistake judgement.
According to the analysis of the measurement error of particle size analyzer,we found that the main reas on of mistake judgement was multi-peak scattering spectrum.Several factors could produce the multi-peak scattering spectrum,such as optical unsymmetry of particles,shape of the particles,beam profile un-uniformity.This paper proposed a inte grating judgement method to avoid the mistake judgement.
2000, 24(5): 301-305.
Abstract:
In this paper,a ray-optics analysisis performed to investigate the asymmetry of dual beam scanning field produced by a rotating polygon.Some basic equations of dual beam scan are derived,such as,the position vector for the incident point,the scalar expression for reflected ray,scan pattern on observation plane ect.The far field asymmetry of the scanning field has been discussed.
In this paper,a ray-optics analysisis performed to investigate the asymmetry of dual beam scanning field produced by a rotating polygon.Some basic equations of dual beam scan are derived,such as,the position vector for the incident point,the scalar expression for reflected ray,scan pattern on observation plane ect.The far field asymmetry of the scanning field has been discussed.
2000, 24(5): 306-311.
Abstract:
By means of dimensional analysis,the hydrodynamic states of lase-rinduced plasma were described.According to the intensity distribution,the lase rinduced plasma can be separated into several regions,and the every parameters of plasma,laser and target materials can be derived to demonstrate a set of scale formulas.This result achieved the theoretical base for rapidly calculate the laser induced plasma parameters.
By means of dimensional analysis,the hydrodynamic states of lase-rinduced plasma were described.According to the intensity distribution,the lase rinduced plasma can be separated into several regions,and the every parameters of plasma,laser and target materials can be derived to demonstrate a set of scale formulas.This result achieved the theoretical base for rapidly calculate the laser induced plasma parameters.
2000, 24(5): 312-317.
Abstract:
This paper deals with the calculating of depth o f laser remelting layers in the plasma sprayed Al2O3 ceramic coatings using infinite half space model and ideal contact double slabs model and the comp aring with the experimental results. The heating and cooling rates can reach 105℃/s and the temperature gradient is about 105℃/mm. The values calculated with the latter model are more approximate to the experimental results than thos e wit h the infinite half space model. The coating design has a strong effect on the remelting depth of ceramic coatings. The remelting depth of single ceramic coat ing reaches to the maximum value.The introduction of bond layer and transition l ayer will reduce the remlting depth. Furthermore, the depth will decrease as the content of doped SiO2 in the coating goes up. For the ceramic coatings with t he same design, the depth of laser remelting layer increases with the output ene rgy density of laser.
This paper deals with the calculating of depth o f laser remelting layers in the plasma sprayed Al2O3 ceramic coatings using infinite half space model and ideal contact double slabs model and the comp aring with the experimental results. The heating and cooling rates can reach 105℃/s and the temperature gradient is about 105℃/mm. The values calculated with the latter model are more approximate to the experimental results than thos e wit h the infinite half space model. The coating design has a strong effect on the remelting depth of ceramic coatings. The remelting depth of single ceramic coat ing reaches to the maximum value.The introduction of bond layer and transition l ayer will reduce the remlting depth. Furthermore, the depth will decrease as the content of doped SiO2 in the coating goes up. For the ceramic coatings with t he same design, the depth of laser remelting layer increases with the output ene rgy density of laser.
2000, 24(5): 318-321.
Abstract:
In this paper,we introdu ce the history and research state of ato mic resonance filter and point out it's developing future.
In this paper,we introdu ce the history and research state of ato mic resonance filter and point out it's developing future.
2000, 24(5): 322-325.
Abstract:
In many fields,such as precise measurements,optical communication and laser processing,the non diffraction beam has useful advantage.Usually,a axial prism was utilized to obtain non-diffraction beam with a fixed θ parameter.In our investigation,we designed a novel optical system to generate a non-diffraction beam with changeable θ parameter.The system includes a negative axial prism and a lens system.In this paper,we proposed the design method of the system,the design parameters and the potential applications.
In many fields,such as precise measurements,optical communication and laser processing,the non diffraction beam has useful advantage.Usually,a axial prism was utilized to obtain non-diffraction beam with a fixed θ parameter.In our investigation,we designed a novel optical system to generate a non-diffraction beam with changeable θ parameter.The system includes a negative axial prism and a lens system.In this paper,we proposed the design method of the system,the design parameters and the potential applications.
2000, 24(5): 325-327.
Abstract:
In order to transmitting the TV signal,we had carefully to consider the P-I relationship and the modul ation performance of the semiconductor laser,and found that the main reason of 3 rd subcarrier inter modulation distortion was the nonlinear relationship between the output and the operating current of the semconductor laser.So we designed an optical transmission system to eliminate the distortion and to transmit color TV signals.
In order to transmitting the TV signal,we had carefully to consider the P-I relationship and the modul ation performance of the semiconductor laser,and found that the main reason of 3 rd subcarrier inter modulation distortion was the nonlinear relationship between the output and the operating current of the semconductor laser.So we designed an optical transmission system to eliminate the distortion and to transmit color TV signals.
