Spectral selectivity in infrared thermal detection

TLDR

Spectrally selective infrared thermal detectors, especially at non‑cryogenic temperatures, rely on phonon and free‑carrier absorption and engineered materials such as patterned grids, nanoparticles, and metamaterials, and their development is driven by advances in nanomechanics and applications from chemical sensing to quantum electrodynamics. The authors aim to outline future research directions for spectrally selective infrared detectors, focusing on architectural innovations, sensitivity improvements, and spectral performance. They analyze background radiation noise for arbitrary spectra and discuss practical design considerations for non‑cryogenic detectors using both natural and engineered materials.

Abstract

A review is made of the physics and technology of spectrally selective thermal detectors, especially those operating at non-cryogenic temperatures. The background radiation noise fluctuations are rederived for arbitrary spectral characteristics. Infrared absorption due to phonons and free carriers is discussed followed by a review of published works on artificial infrared absorption materials such as patterned grids, nanoparticles, plasmonic structures, metamaterials and others. Subsequently, the literature of the spectral characteristics of broadband thermal detectors and spectrally selective thermal detectors is reviewed. Finally, the authors speculate on the directions that future research and development in the area will take regarding architectures, sensitivity and spectral characteristics. Advances in nanomechanical structures and thermal-emission devices have provided fresh perspectives for the development of infrared thermal detectors. Joseph Talghader and colleagues at the University of Minnesota, USA, review fundamental and technological progress in the field from the perspective of spectrally selective detection, which is important for applications ranging from chemical detection and target recognition to studies in cavity quantum electrodynamics. Placing emphasis on devices operating at non-cryogenic temperatures, Talghader et al. discuss basic and practical aspects of detectors based on both natural and artificial materials. They round off their discussion by looking at current trends in material science and imaging technology to speculate about the future directions of the field.