Synchronously wired infrared antennas for resonant single-quantum-well photodetection up to room temperature

Hideki T Miyazaki,Kazuhiro Watanabe,Akitsu Shigetou,Hirotaka Osato,Yukinaga Arai,Takaaki Mano,Takeshi Kasaya,Yoshimasa Sugimoto,Hiroshi Miyazaki,Yoji Jimba,Takuya Kawazu,Tetsuyuki Ochiai

doi:10.1038/s41467-020-14426-6

Hideki T Miyazaki, Kazuhiro Watanabe + Show 10 more

Open Access

https://doi.org/10.1038/s41467-020-14426-6

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Abstract

Optical patch antennas sandwiching dielectrics between metal layers have been used as deep subwavelength building blocks of metasurfaces for perfect absorbers and thermal emitters. However, for applications of these metasurfaces for optoelectronic devices, wiring to each electrically isolated antenna is indispensable for biasing and current flow. Here we show that geometrically engineered metallic wires interconnecting the antennas can function to synchronize the optical phases for promoting coherent resonance, not only as electrical conductors. Antennas connected with optimally folded wires are applied to intersubband infrared photodetectors with a single 4-nm-thick quantum well, and a polarization-independent external quantum efficiency as high as 61% (responsivity 3.3 A W−1, peak wavelength 6.7 μm) at 78 K, even extending to room temperature, is demonstrated. Applications of synchronously wired antennas are not limited to photodetectors, but are expected to serve as a fundamental architecture of arrayed subwavelength resonators for optoelectronic devices such as emitters and modulators.

Highlights

Optical patch antennas sandwiching dielectrics between metal layers have been used as deep subwavelength building blocks of metasurfaces for perfect absorbers and thermal emitters
QW infrared photodetectors (QWIPs) absorb infrared light based on intersubband transitions (ISBT) and generate a photoconductive current by applying a bias voltage
There is no sensitivity to normal incidence, and techniques such as oblique incidence and diffraction gratings are required. Another drawback is the low absorption of ISBT compared to the interband transition. Both of these problems can be overcome by incorporating QWIPs into optical patch antennas

Summary

Introduction

Optical patch antennas sandwiching dielectrics between metal layers have been used as deep subwavelength building blocks of metasurfaces for perfect absorbers and thermal emitters. Phase-gradient metasurfaces, which create arbitrary wavefronts using arrays of deep subwavelength antennas with unequal shapes, have given rise to a new frontier in metamaterials that had previously focused on three-dimensional bulk materials[4] In these metasurfaces, the spacing between the antennas is smaller than the wavelength, but not too small to avoid strong near-field mutual coupling. Metallic wires folded to provide optimum optical phase delay electrically connect (short-circuit) the patch antennas, without disrupting the optimized antenna resonance In this Article, we clarify the physical foundations underlying the SWAs, and present their application to mid-infrared photodetectors incorporating only a single quantum well (QW). Applications are not limited to detectors; SWAs offer greater design freedom as a fundamental platform for optoelectronic metadevices[19,20,21]

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