Oh Sungkyun, Bae Sangeun, Carter Campbell D, Do Hyungrok
Opt Lett. 2019 Aug 1;44(15):3721-3724. doi: 10.1364/OL.44.003721.
Nanosecond laser pulses (6 ns FWHM, produced by a Q-switched, frequency-doubled Nd:YAG laser) are chopped using the inverse-Bremsstrahlung (IB) photon absorption process in a cell with variable pressure. The IB process that quickly absorbs the majority of the laser pulse energy is triggered by focusing the pulse in the cell. Prior to the initiation of the IB process, the gaseous medium in the cell is transparent, while it suddenly becomes opaque with the IB process activated; therefore, the pressure cell can be used as a virtual optical shutter. The shutter "closing time" depends strongly on the pressure of the cell and the laser pulse energy and thus can be controlled. Dependence of the "closing time" on these two parameters is experimentally investigated.
纳秒激光脉冲（由调Q倍频Nd:YAG激光器产生，半高宽为6 ns）在可变压力的气室中利用逆轫致辐射（IB）光子吸收过程进行斩波。通过将脉冲聚焦在气室中来触发能快速吸收大部分激光脉冲能量的IB过程。在IB过程启动之前，气室内的气态介质是透明的，而在IB过程激活时它会突然变得不透明；因此，压力气室可用作虚拟光学快门。快门的“关闭时间”强烈依赖于气室压力和激光脉冲能量，因而可以控制。通过实验研究了“关闭时间”对这两个参数的依赖性。
