Key Laboratory for Laser Plasmas (Ministry of Education), Department of Physics and Astronomy, Shanghai Jiao Tong University, Shanghai 200240, China.
Collaborative Innovation Center of IFSA (CICIFSA), Shanghai Jiao Tong University, Shanghai 200240, China.
Nat Commun. 2016 Jun 10;7:11893. doi: 10.1038/ncomms11893.
Optical modulators can have high modulation speed and broad bandwidth, while being compact. However, these optical modulators usually work for low-intensity light beams. Here we present an ultrafast, plasma-based optical modulator, which can directly modulate high-power lasers with intensity up to 10(16) W cm(-2) to produce an extremely broad spectrum with a fractional bandwidth over 100%, extending to the mid-infrared regime in the low-frequency side. This concept relies on two co-propagating laser pulses in a sub-millimetre-scale underdense plasma, where a drive laser pulse first excites an electron plasma wave in its wake while a following carrier laser pulse is modulated by the plasma wave. The laser and plasma parameters suitable for the modulator to work are based on numerical simulations.
光学调制器具有调制速度快、带宽宽、结构紧凑等优点。然而，这些光学调制器通常适用于低强度光束。在这里，我们提出了一种超快等离子体光学调制器，它可以直接调制强度高达 10(16) W cm(-2)的高功率激光，产生具有超过 100%的分数带宽的极宽带宽，在低频侧扩展到中红外区域。该概念依赖于在亚毫米尺度下的弱等离子体中传播的两个共线激光脉冲，其中驱动激光脉冲首先在其尾迹中激发电子等离子体波，而后续的载波激光脉冲被等离子体波调制。适合调制器工作的激光和等离子体参数是基于数值模拟得到的。
