Contactless Multicolor Infrared Detection

Abstract

The next generation of infrared (IR) detectors will enable revolutionary advances in multicolor hyperspectral capabilities, which warrant the development of multicolor detectors. While many schemes of dual-color IR detection are reported in the literature, there are few detectors which can independently address three or more colors and have drawbacks such as requiring postgrowth fabrication steps and significant crosstalk between colors. Here we demonstrate a contactless photoconductive IR detection architecture that overcomes these challenges and can detect and independently address multiple IR colors on a single busline by using different microwave frequencies. Our design couples photoconductive absorbers to the near-fields of unique modes in a single high permittivity (ε ∼ 80) dielectric microwave resonator driven by a continuous wave microwave source. Absorbed light in each photoconductor generates electron hole pairs, which correspondingly add losses to the specific resonator mode and increase the microwave signal transmitted at the respective resonant frequency. Each unique dielectric resonator mode interacts with a photoconductor of different bandgap enabling independent coverage and addressability at disparate wavelengths including near-infrared using silicon, short-wave infrared using germanium, and midwave infrared using mercury cadmium telluride. This detection architecture does not require complex growth methods, band offset engineering, optimized doping, mesa etches, or contact formation, opening the door to practical multicolor light detection across the spectrum.