Spectrally Selective Infrared Absorption Enhancement in Photonic Crystal Cavities

Infrared photodetectors with spectrally selective response are highly desirable for applications such as hyper-spectral imaging and gas sensing. Owing to the ability of photonic density of states modification and dispersion engineering, photonic crystals appear to be one of the most promising platforms for infrared photodetectors with spectrally-selective absorption enhancement. We report here the latest advances on 1D and 2D dielectric photonic crystal structures for infrared photodetectors, based on defect mode, bandedge effect and the guided mode resonance/Fano effects. High spectral selectivity and tunability is feasible with defect mode engineering, making photonic crystal defect cavities a promising nanophotonic platform for the spectrally selective infrared sensing and hyper-spectral imaging, with the incorporation of quantum well or quantum dot infrared photodetector heterostructures.