Demonstration of mid-wave and long-wave resonant cavity infrared detectors at SK Infrared

Infrared detectors and imaging systems are widely used across industrial and defense sectors, but performance demands continue to exceed the limits of traditional cooled, broadband imagers. This work highlights sensor technologies developed to meet specialized requirements through tailored design, fabrication, and characterization. SK Infrared has advanced resonant cavity infrared detectors (RCIDs) using III-V compound semiconductor superlattices grown by molecular beam epitaxy, enabling mid-wave infrared (MWIR) and long-wave infrared (LWIR) operation at elevated temperatures above 200 K. These structures can be wavelength-selective and deliver solid-state performance by leveraging a thin absorber embedded within an optical cavity formed by a Distributed Bragg Reflector (DBR) and a metallic back mirror to achieve narrow-band spectral selectivity and enhanced quantum efficiency. We report the design, fabrication, and experimental RCID demonstration of a MWIR narrow spectral bandwidth of 70 nm and specific detectivity approaching 3 x 10¹⁰ Jones near 4.2 and 4.8 μm at 200 K. In the LWIR, the RCIDs were designed for 10 μm wavelength operation and exhibited resonant enhancement of approximately 50 times their non-resonant response approaching 1.4 x 10¹¹ Jones, with peak quantum efficiency reaching 41% and full width at half maximum (FWHM) of 126 nm at an operating temperature of 125 K. These results establish a scalable path toward spectrally resolved infrared sensors, enabling compact, high-resolution, non-dispersive infrared technology addressing the growing need for high-performance, cost-effective solutions across multiple spectral bands for defense and commercial sensing applications.