摘要
利用傅里叶积分变换法研究了超短脉冲高斯光束通过透镜的聚焦特性 ,给出了透镜焦平面上光强的空间、时间分布 ,以及能量密度分布。在所用数学处理中未使用缓变包络近似 ,结果对于包括单周期超短脉冲情况都是成立的。数值计算结果和物理分析表明 ,不考虑色散时 ,焦点附近的脉冲宽度相对于初始脉冲几乎不变。对于色散透镜 ,研究了透镜色差和群速度色散影响。透镜色差使焦点附近的脉冲 (特别是脉冲前沿 )显著展宽 ,能量密度分布展宽 ,峰值功率降低。群速度色散会进一步使脉冲展宽 ,脉冲前沿出现振荡 ,峰值功率降低 ,但它对脉冲光束的能量密度分布影响很小。更高阶的色散效应影响较小。
Based on the Fourier transform, the focusing of ultrashort pulsed Gaussian beams by a lens is studied. Spatial and temporal intensity distributions and energy density of focused ultrashort pulsed Gaussian beams at the focal plane are presented. In authors′ mathematical treatment the slowly varying envelope approximation is not used, so the results are valid for the more general case including single-cycle ultrashort pulses. Numerical results and physical analysis are given. It is shown that, in nondispersive case the pulse duration in the vicinity of the focus remains nearly unchanged as compared with that of the input pulse. For dispersive lens the influence of the lens chromatic aberration and group velocity dispersion is studied. The lens chromatic aberration leads to a drastic broadening of the pulse form (especially in its front) and the energy density distribution and to a decrease of the peak intensity. The group velocity dispersion results in a further broadening of the pulse form, an oscillation in its front and a further decrease of the peak intensity, whereas it has little effect on the energy density distribution. The higher-order dispersions play a relatively minor role.
出处
《光学学报》
EI
CAS
CSCD
北大核心
2004年第6期798-802,共5页
Acta Optica Sinica
基金
激光技术国家重点实验室基金资助课题
关键词
超短脉冲高斯光束
色散透镜
聚焦特性
色差
群速度色散
傅里叶积分变换
laser technique
ultrashort pulsed Gaussian beam
dispersive lens
focusing property
chromatic aberration
group velocity dispersion
