Plasma optical modulators for intense lasers

TL;DR

This paper introduces a novel plasma-based optical modulator capable of handling extremely high power lasers, producing broad spectra and extending into the mid-infrared, with potential applications in high field physics.

Contribution

It presents the first ultrafast, plasma-based optical modulator that can directly modulate high power lasers at intensities up to 10^16 W/cm^2.

Findings

Achieves fractional bandwidth over 100%

Extends modulation into the mid-infrared regime

Operates with laser intensities up to 10^16 W/cm^2

Abstract

Optical modulators can be made nowadays with high modulation speed, broad bandwidth, while being compact, owing to the recent advance in material science and microfabrication technology. 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 level 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 beams in a sub-mm-scale underdense plasma, where a drive laser pulse first excites an electron plasma wave in its wake while a following carrier laser beam is modulated by the plasma wave. The laser and plasma parameters suitable for the modulator to work are presented. Such optical modulators may enable new applications in the high field physics.