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

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.

Kirchhoff’s Thermal Radiation from Lithography-Free Black Metals

“…Metasurface absorbers, composed of patterns of sub-wavelength antennas, are used for tailoring spectral, polarisation and angular dependencies of electromagnetic radiation absorption as well as thermal radiation emission [ 1 , 2 , 3 , 4 , 5 , 6 , 7 , 8 , 9 , 10 , 11 ]. The Kirchhoff’s law of thermal radiation describes the equivalence between absorptivity and emissivity, which is important in applications of thermal radiation and IR light sources for mid infrared (IR) sensors [ 12 , 13 , 14 , 15 , 16 , 17 , 18 , 19 , 20 , 21 , 22 , 23 , 24 ]. The radiant output power can easily be tuned by heating of metasurfaces to high values enabled by established commercial light emitting diodes or quantum cascade lasers in mid-IR spectral range.…”

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

“…The QWIP layer used in this study consists of a single 4 nm GaAs quantum well layer sandwiched by two 50 nm Al 0.3 Ga 0.7 As barrier layers and two 48 nm GaAs contact layers [21,25,32], a total thickness T = 200 nm, which exhibits a photoconductive responsivity peak at 6.7 μm [21,25]. Stripe cavities consist of a t m1 = 100 nm thick Au stripe and a thick Au substrate (650 nm, but set at t m2 = 200 nm for calculations) sandwiching the QWIP layer.…”

“…Stripes with widths of L 1 and L 2 (L 1 < L 2 ) are alternated with a period P/2 ( Figure 1A). The QWIP layer between the QWIP stripes is removed [21,25] for electrical isolation between neighboring stripes. The resonance wavelengths λ 1 and λ 2 , determined by L 1 and L 2 , respectively, should fall within the absorption range of the quantum well (6.0-7.4 μm).…”

“…Here, we demonstrate a dual-band photodetector for NDIR gas sensing based on resonant photon sorting consisting of two electrically isolated, interdigitated stripe MDM cavities sandwiching quantum well infrared photodetectors (QWIPs), metasurface QWIPs [21][22][23][24][25], with different resonance wavelengths. Metasurface QWIPs are based on intersubband transitions (ISBT) in quantum wells.…”

“…An intense vertical electric field, essential for ISBT absorption [26,27], is provided by the MDM cavity through rotation of the incident horizontal electric field to vertical, and intensity enhancement [14,28,29]. High responsivities [23], fast response times [24,30], and detectivities approaching theoretical limits [21,24,25,31], sufficient to replace toxic HgCdTe presently dominant at wavelengths beyond 5 μm, have been demonstrated.…”