Metallic and dielectric metasurfaces in photoconductive terahertz devices: a review

Alexander E. Yachmenev,Rustam A. Khabibullin,Denis V. Lavrukhin,Igor A. Glinskiy,Yurii G. Goncharov,Nikolay V. Zenchenko,Taiichi Otsuji,Dmitry S. Ponomarev,Igor E. Spektor

doi:10.1117/1.oe.59.6.061608

Alexander E. Yachmenev, Rustam A. Khabibullin + Show 7 more

Open Access

https://doi.org/10.1117/1.oe.59.6.061608

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Abstract

This review highlights recent and novel trends focused on metallic (plasmonic) and dielectric metasurfaces in photoconductive terahertz (THz) devices. We demonstrate the great potential of its applications in the field of THz science and technology, nevertheless indicating some limitations and technological issues. From the state-of-the-art, the metasurfaces are, by far, able to force out previous approaches like photonic crystals and are capable of significantly increasing the performance of contemporary photoconductive devices operating at THz frequencies.

Highlights

We briefly summarize some of the recent approaches aimed at the enhancement of optical-to-THz conversion efficiency in photoconductive antennas (PCAs) by implementation of various metallic and dielectric metasurfaces in the antenna’s photoconductive gap
The one promising approach seems to be transparent-conducting oxides (TCOs) that can be used as a metasurface material for the PCAs due to smaller losses compared with noble metals.[94,95,96]
To the plasmonic metasurfaces, the dielectric metasurfaces have attracted a significant interest in recent years because they can efficiently neutralize the drawbacks of plasmonic structures

Summary

Introduction

The terahertz (THz) frequency range has found wide applications in many fields ranging from condensed matter physics[1,2,3,4] and material science[5,6] to gas sensing[7,8,9] and pharmaceutical industry[10] as well as various security[11,12,13,14,15,16] and biomedical[17,18,19,20,21,22] applications. PCAs’ efficiency is limited by the amount of the energy of an absorbed optical radiation, relatively low mobility of photocarriers in photoconductive substrates,[25,26,27] screening effects,[28,29] and a semiconductor breakdown threshold voltage.[30,31] The increase in the PCA performance is predominantly associated with an efficient optical light confinement in the antenna’s gap that can be reached due to metasurface implementation The latter allows the manipulation of phase, amplitude, and polarization of an incident radiation with high spatial resolution.

Metallic Metasurfaces

Dielectric Metasurfaces

Findings

Conclusions