Near-field resonant photon sorting applied: dual-band metasurface quantum well infrared photodetectors for gas sensing

Nanophotonics

article

Mel F. Hainey¹  Yukinaga Arai¹  Akitsu Shigetou¹  Hideki T. Miyazaki¹  Takaaki Mano¹  Takeshi Kasaya¹  Tetsuyuki Ochiai¹  Hirotaka Osato¹  Kazuhiro Watanabe¹  Yoshimasa Sugimoto¹  Takuya Kawazu¹ 

[1] National Institute for Materials Science

关键词: infrared photodetector;    metasurface;    nanophotonics;    NDIR sensing;    photon sorting;    quantum well;   

DOI  :  10.1515/nanoph-2020-0456

学科分类：社会科学、人文和艺术（综合）

来源: De Gruyter

【 摘 要 】

Two photodetectors for measuring transmission and two bulky, separated narrowband filters for picking a target gas absorption line and a non-absorbing reference from broadband emission are typically required for dual-band non-dispersive infrared (NDIR) gas sensing. Metal-dielectric-metal (MDM) metasurface plasmon cavities, precisely controllable narrowband absorbers, suggest a next-generation, nanophotonic approach. Here, we demonstrate a dual-band MDM cavity detector that consolidates the function of two detectors and two filters into a single device by employing resonant photon sorting-a function unique to metasurfaces. Two MDM cavities sandwiching a quantum well infrared photodetector (QWIP) with distinct resonance wavelengths are alternately arranged in a subwavelength period. The large absorption cross section of the cavities ensures ~95% efficient lateral sorting of photons by wavelength into the corresponding detector within a near-field region. The flow of incident photons is thus converted into two independent photocurrents for dual-band detection. Our dual-band photodetectors show competitive external quantum efficiencies up to 38% (responsivity 2.1 A/W, peak wavelength 6.9 5m) at 78 K. By tailoring one resonance to an absorption peak of NO 2 (6.25 5m) and the other to a non-absorbing reference wavelength (7.15 5m), NDIR NO 2 gas sensing with 10 ppm accuracy and 1 ms response times is demonstrated. Through experiment and numerical simulation, we confirm near-perfect absorption at the resonant cavity and suppressed absorption at its non-resonant counterpart, characteristic of resonant photon sorting. Dual-band sensing across the mid-infrared should be possible by tailoring the cavities and quantum well to desired wavelengths.

【 授权许可】

CC BY