为了研究频带宽度对激光光束传输和激光应用产生的影响, 采用衍射积分推导了矩形谱宽带激光通过双焦色散透镜后的传输公式, 利用数值计算研究了矩形谱宽带激光带宽诱导的焦开关现象, 分析得到带宽对光强分布和焦开关的影响。结果表明, 带宽是影响光强分布和焦开关形成的重要因素; 带宽变化会导致光强分布中光强主极大从一个位置跃变到另一个位置, 从而形成焦开关现象。该研究结果有助于进一步推动宽频带激光的应用。

In order to research the effects of frequency bandwidth on the propagation and applications of broadband laser, the propagation formula of broadband laser with rectangular spectrum passing through a bifocal dispersion lens system was derived by using diffraction integral. Bandwidth-induced focal switch in broadband laser with rectangular spectrum is studied by numerical calculation. The effects of bandwidth on the intensity distribution and focal switch were analyzed. The results show that bandwidth is an important factor affecting intensity distribution and focal switch. Primary maximum intensity of the focused broadband laser can rapidly bounce from one place to another with the variety of bandwidth and then the focal switch is generated. The results are helpful for further applications of broadband laser.