Tunalbe coherent extreme ultraviolet radiation has been produced in nitrogen by third harmonic generation(THG)processes enhanced by two-photon resonance with the a^(1)II_(g)(v'=1)state and three-photon resonance w...Tunalbe coherent extreme ultraviolet radiation has been produced in nitrogen by third harmonic generation(THG)processes enhanced by two-photon resonance with the a^(1)II_(g)(v'=1)state and three-photon resonance with the c'_(4)^(1)Σ_(u)^(+)(v'=1)state,respectively.The highly resolved THG spectra imply that THG can be used to probe the higher excited states and to detect the rotational population of a molecular gas.展开更多
Methane has been used as a nonlinear optical medium to produce tunable coherent vacuum ultraviolet and extreme ultraviolet radiation.A vibrational structure with a vibrational frequency of 820cm^(-1) was observed in a...Methane has been used as a nonlinear optical medium to produce tunable coherent vacuum ultraviolet and extreme ultraviolet radiation.A vibrational structure with a vibrational frequency of 820cm^(-1) was observed in a highly resolved third harmonic spectrum.This proved that third harmonic generation is an effective method to probe the higher excited states of molecular gases.展开更多
Tunable coherent extreme ultraviolet radiation has been generated in CO by two-photon resonant third harmonic generation via the A^(1) II(v'=4)←X^(1)Σ+(v"=0)transition.The third nharmonic spectrum exhibits ...Tunable coherent extreme ultraviolet radiation has been generated in CO by two-photon resonant third harmonic generation via the A^(1) II(v'=4)←X^(1)Σ+(v"=0)transition.The third nharmonic spectrum exhibits resolved and improved rotational lines due to the expansion cooling of the molecular beam.The saturation and the phase-matching of the nonlinear process are also discussed.展开更多
Tunable coherent vacuum ultraviolet and extreme ultraviolet radiation have been produced in H2 by three-photon resonant third harmonic generation via B1 Σ_(u)^(+)(v’) ← X^(1) Σ_(g)^(+) (v = 0 ) and C^(1) IIu(v’) ...Tunable coherent vacuum ultraviolet and extreme ultraviolet radiation have been produced in H2 by three-photon resonant third harmonic generation via B1 Σ_(u)^(+)(v’) ← X^(1) Σ_(g)^(+) (v = 0 ) and C^(1) IIu(v’) ← X^(1) Σ_(g)^(+) ( v = 0 ) transitions. Highly resolved third harmonic spectrum exhibits some distinct characteristics. Phase-matching effect of the nonlinear optical process is also discussed.展开更多
Broadly tunable coherent VUV/XUV radiations from 92 to 145 nm were generated by nonresonant four-wave sum-mixing (FWSM) and third-harmonic generation (THG) in pulsed jet of Xe or Kr. The dependence of phase-matching o...Broadly tunable coherent VUV/XUV radiations from 92 to 145 nm were generated by nonresonant four-wave sum-mixing (FWSM) and third-harmonic generation (THG) in pulsed jet of Xe or Kr. The dependence of phase-matching on gas density, atomic dispersion was observed. THG enhanced by third-photon resonant with the high Rydberg states in Xe was observed, and the resolved principal quantum number was up to 34.展开更多
Tunable coherent radiation of wavelength between 92 nm and 122 nm has been produced in molecular gases of N2, CO, H2 and CH4 by resonant and nonresonant third harmonic generation. Factors with respect to the frequency...Tunable coherent radiation of wavelength between 92 nm and 122 nm has been produced in molecular gases of N2, CO, H2 and CH4 by resonant and nonresonant third harmonic generation. Factors with respect to the frequency conversion efficiency, including the line strength of the nonlinear susceptibility, the density of the media and the phase-matching, are discussed. By analyzing the characteristics of the four-wave mixing spectra in molecular gases, some physical parameters and the population of the energy levels are obtained. This indicates that nonlinear optical frequency conversion process provides a useful method to study the structure and spectra of molecules.展开更多
Tunable coherent radiations in the range of 83-170nm have been generated in Xe,Kr and Ar by resonant and nonresonant four-wave sum-mixing,four-wave sum-differenoe-mixing and third harmonic processes.The physical mecha...Tunable coherent radiations in the range of 83-170nm have been generated in Xe,Kr and Ar by resonant and nonresonant four-wave sum-mixing,four-wave sum-differenoe-mixing and third harmonic processes.The physical mechanism for the generation of the coherent XUV/VUV radiations is investigated.Broadly tunable coherent radiation was generated by nonresonant four-wave sum-mixing for the first time below the first resonance level of nonlinear media,and multicoherence length interference between the driving polarization and induced radiation was observed.展开更多
基金Supported by the High Technology Program of Lasers(863-410)the National Natural Science Foundation of China under Grant No.19584001.
文摘Tunalbe coherent extreme ultraviolet radiation has been produced in nitrogen by third harmonic generation(THG)processes enhanced by two-photon resonance with the a^(1)II_(g)(v'=1)state and three-photon resonance with the c'_(4)^(1)Σ_(u)^(+)(v'=1)state,respectively.The highly resolved THG spectra imply that THG can be used to probe the higher excited states and to detect the rotational population of a molecular gas.
基金Supported by the High Technology Program of Lasers(863-410)the National Natural Science Foundation of China under Grant No.19584001.
文摘Methane has been used as a nonlinear optical medium to produce tunable coherent vacuum ultraviolet and extreme ultraviolet radiation.A vibrational structure with a vibrational frequency of 820cm^(-1) was observed in a highly resolved third harmonic spectrum.This proved that third harmonic generation is an effective method to probe the higher excited states of molecular gases.
基金Supported by the High Technology Program of Lasers(863-410)the National Natural Science Foundation of China under Grant No.19584001.
文摘Tunable coherent extreme ultraviolet radiation has been generated in CO by two-photon resonant third harmonic generation via the A^(1) II(v'=4)←X^(1)Σ+(v"=0)transition.The third nharmonic spectrum exhibits resolved and improved rotational lines due to the expansion cooling of the molecular beam.The saturation and the phase-matching of the nonlinear process are also discussed.
基金the National High Technology Program of Lasers(863-410).
文摘Tunable coherent vacuum ultraviolet and extreme ultraviolet radiation have been produced in H2 by three-photon resonant third harmonic generation via B1 Σ_(u)^(+)(v’) ← X^(1) Σ_(g)^(+) (v = 0 ) and C^(1) IIu(v’) ← X^(1) Σ_(g)^(+) ( v = 0 ) transitions. Highly resolved third harmonic spectrum exhibits some distinct characteristics. Phase-matching effect of the nonlinear optical process is also discussed.
基金National Natural Science Foundation of ChinaHigh Technoque Program of Lasers.
文摘Broadly tunable coherent VUV/XUV radiations from 92 to 145 nm were generated by nonresonant four-wave sum-mixing (FWSM) and third-harmonic generation (THG) in pulsed jet of Xe or Kr. The dependence of phase-matching on gas density, atomic dispersion was observed. THG enhanced by third-photon resonant with the high Rydberg states in Xe was observed, and the resolved principal quantum number was up to 34.
文摘Tunable coherent radiation of wavelength between 92 nm and 122 nm has been produced in molecular gases of N2, CO, H2 and CH4 by resonant and nonresonant third harmonic generation. Factors with respect to the frequency conversion efficiency, including the line strength of the nonlinear susceptibility, the density of the media and the phase-matching, are discussed. By analyzing the characteristics of the four-wave mixing spectra in molecular gases, some physical parameters and the population of the energy levels are obtained. This indicates that nonlinear optical frequency conversion process provides a useful method to study the structure and spectra of molecules.
基金Project supported by the National Natural Science Foundation of ChinaHigh-Tech Program of China in Laser Area
文摘Tunable coherent radiations in the range of 83-170nm have been generated in Xe,Kr and Ar by resonant and nonresonant four-wave sum-mixing,four-wave sum-differenoe-mixing and third harmonic processes.The physical mechanism for the generation of the coherent XUV/VUV radiations is investigated.Broadly tunable coherent radiation was generated by nonresonant four-wave sum-mixing for the first time below the first resonance level of nonlinear media,and multicoherence length interference between the driving polarization and induced radiation was observed.
