Design and analysis of electrothermal metasurfaces

TL;DR

This paper investigates finite-size electrothermal metasurfaces made of gold nanorods, demonstrating rapid response times and tunable temperature uniformity, advancing practical thermal infrared control.

Contribution

It reveals that small finite arrays of gold nanorods can achieve near-infinite resonance properties with nanosecond response times and tunable temperature uniformity.

Findings

Finite arrays achieve resonance close to infinite cases.

Response time can be reduced to nanoseconds.

Temperature uniformity can be tuned to sub-Kelvin levels.

Abstract

Electrothermal metasurfaces have attracted extensive attention due to their ability to dynamically control thermal infrared radiation. Although previous studies were mainly focused on the metasurfaces with infinite unit cells, the finite-size effect can be a critical design factor for developing thermal metasurfaces with fast response and broad temperature uniformity in practice. Here, we study the thermal metasurfaces consisting of gold nanorods with a finite array size, which, with only several periods, can achieve a resonance close to that of the infinite case. More importantly, such a small footprint due to the finite array size results in the response time down to a nanosecond level. Furthermore, the number of the unit cells in the direction perpendicular to the axis of the nanorods is found to be insensitive to the resonance and response time, thus providing a tunability in aspect ratio that can boost the temperature uniformity in the sub-Kelvin level.