Infrared Spectroscopy via Selective Thermal Emission of Two Layer Perfect Absorber

Abstract

Strong absorption (and corresponding emission) from a two-layer system consisting of heavily doped silicon and a high-index germanium dielectric layer is studied. Absorption resonances in the mid-infrared via electrical resistive heating have also been demonstrated to be polarization and angle dependent. Such structures have the potential for applications in thermal signature mimicry, thermal cloaking, and frequency selective infrared sources. The simplicity of fabrication (requiring no photolithographic process) allows for inexpensive and rapid deployment of this engineered structure. In this work, a selective electrical pulsing system is presented and tested to resistively heat a group of germanium-on-silicon samples at a determined pulse frequency. Such a system can conceivably be used to create a cheap infrared spectral imaging system when emissions in the time-domain are resolved approximately.