原子在红外激光场中产生高次谐波及阿秒脉冲随波长的变化规律

摘要

利用强场近似理论,研究了在长波红外激光场(波长800-2000nm)驱动下氢原子产生的高次谐波,分析了在截止位置附近高次谐波的转换效率随激光波长的变化规律.发现在截止位置附近原子发射高次谐波的转换效率比平台区域的转换效率低,但获得的阿秒脉冲的宽度会随波长的增大而缩短.%Basing on the strong-field approximation, we study high harmonic generation of hydrogen atom exposed to the long wavelength infrared laser field, and analyze the wavelength dependence of conversion efficiency of high-order harmonic generation near the cut-off position. It is found that high-order harmonic yield is much lower near cut-off than in the beginning of the plateau of the harmonic generation, but the width of the attosecond pulse is narrowed with increasing wavelength.