Broadband amplification of light through adiabatic spatiotemporal modulation

TL;DR

This paper proposes a theoretical method for broadband light amplification using adiabatic spatiotemporal modulation, overcoming the limitations of rapid modulation requirements in four-dimensional optics.

Contribution

It introduces a novel broadband gain mechanism via adiabatic modulation patterns, compatible with epsilon-near-zero and bianisotropic media, enabling new ultrafast optical applications.

Findings

Broadband amplification achieved without sub-cycle temporal responses.

Compatible with epsilon-near-zero materials and bianisotropic media.

Potential for generating high-energy, ultrashort optical pulses.

Abstract

Four-dimensional optics leverages the simultaneous control of materials in space and time to manipulate light. A key challenge in experimentally realizing many intriguing phenomena is the need for rapid modulation, which is hindered by the inherently adiabatic relaxation of optical materials. Here, we theoretically demonstrate that broadband amplification can be achieved without the need for sub-cycle temporal responses, instead leveraging adiabatic spatiotemporal modulation patterns. The proposed modulation scheme is compatible with recent demonstrations of the temporal modulation of epsilon-near-zero materials. We also show that the same phenomenon may be realized by modulating bianisotropic nonreciprocal media in time. This broadband gain mechanism opens new avenues for the generation of high-energy, ultrashort optical pulses, with potential impact in ultrafast optics and electron microscopy.