Intersubband polaritonic metasurfaces for high-contrast ultra-fast power limiting and optical switching

TL;DR

This paper demonstrates the design and optimization of intersubband polaritonic metasurfaces that achieve high-contrast, ultrafast optical switching and power limiting in the mid-infrared, with potential for even higher performance.

Contribution

It introduces a synergistic approach to optimize materials and nanostructures for ultrafast polaritonic metasurfaces, achieving record-high reflection contrast in power limiters.

Findings

Record-high reflection contrast of 54% achieved experimentally.

Optimized semiconductor heterostructures reduce linewidth and absorption.

Potential to reach 94% reflection contrast with all-dielectric metasurfaces.

Abstract

Nonlinear intersubband polaritonic metasurfaces support one of the strongest known ultrafast nonlinear responses in the mid-infrared frequency range across all condensed matter systems. Beyond harmonic generation and frequency mixing, these nonlinearities can be leveraged for ultrafast optical switching and power limiting, based on tailored transitions from strong to weak polaritonic coupling. Here, we demonstrate synergistic optimization of materials and photonic nanostructures to achieve large reflection contrast in ultrafast polaritonic metasurface limiters. The devices are based on optimized semiconductor heterostructure materials that minimize the intersubband transition linewidth and reduce absorption in optically saturated nanoresonators, achieving a record-high reflection contrast of 54% experimentally. We also discuss opportunities to further boost the metrics of performance of this class of ultrafast limiters, showing that reflection contrast as high as 94% may be realistically achieved using all-dielectric intersubband polaritonic metasurfaces.