We numerically study the propagation dynamics of intense optical pulses in gas-filled hollow-core fibers（HCFs）. The spatiotemporal dynamics of the pulses show a transition from tightly confined to loosely confined c...We numerically study the propagation dynamics of intense optical pulses in gas-filled hollow-core fibers（HCFs）. The spatiotemporal dynamics of the pulses show a transition from tightly confined to loosely confined characteristics as the fiber core is increased, which manifests as a deterioration in the spatiotemporal uniformity of the beam. It is found that using the gas pressure gradient does not enhance the beam quality in large-core HCFs, while inducing a positive chirp in the pulse to lower the peak power can improve the beam quality. This indicates that the self-focusing effect in the HCFs is the main driving force for the propagation dynamics. It also suggests that pulses at longer wavelengths are more suitable for HCFs with large cores because of the lower critical power of self-focusing, which is justified by the numerical simulations. These results will benefit the generation of energetic few-cycle pulses in large-core HCFs.展开更多
The wavelength dependence of electron localization of H2^＋ and its isotopomers in the ultraviolet pump-probe scheme is investigated by numerically solving the time-dependent Schrodinger equation. By combining with a ...The wavelength dependence of electron localization of H2^＋ and its isotopomers in the ultraviolet pump-probe scheme is investigated by numerically solving the time-dependent Schrodinger equation. By combining with a semiclassical method,an effective analytical formula expressed in the adiabatic representation is established to describe the localization probability with several zero crossings. A stable zone with respect to the laser intensity and carrier envelope phase is found at a relatively long probe wavelength. Finally, the critical probe wavelengths to reach at the stable zone are derived by using the three-dimensional model. Slower nuclear motion of heavier isotopomers leads to a longer critical wavelength.展开更多
文摘We numerically study the propagation dynamics of intense optical pulses in gas-filled hollow-core fibers（HCFs）. The spatiotemporal dynamics of the pulses show a transition from tightly confined to loosely confined characteristics as the fiber core is increased, which manifests as a deterioration in the spatiotemporal uniformity of the beam. It is found that using the gas pressure gradient does not enhance the beam quality in large-core HCFs, while inducing a positive chirp in the pulse to lower the peak power can improve the beam quality. This indicates that the self-focusing effect in the HCFs is the main driving force for the propagation dynamics. It also suggests that pulses at longer wavelengths are more suitable for HCFs with large cores because of the lower critical power of self-focusing, which is justified by the numerical simulations. These results will benefit the generation of energetic few-cycle pulses in large-core HCFs.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.11404153,11135002,11475076,and 11405077)the Fundamental Research Funds for the Central Universities of China(Grants Nos.lzujbky-2016-29,lzujbky-2016-31,and lzujbky-2016-209)
文摘The wavelength dependence of electron localization of H2^＋ and its isotopomers in the ultraviolet pump-probe scheme is investigated by numerically solving the time-dependent Schrodinger equation. By combining with a semiclassical method,an effective analytical formula expressed in the adiabatic representation is established to describe the localization probability with several zero crossings. A stable zone with respect to the laser intensity and carrier envelope phase is found at a relatively long probe wavelength. Finally, the critical probe wavelengths to reach at the stable zone are derived by using the three-dimensional model. Slower nuclear motion of heavier isotopomers leads to a longer critical wavelength.
