Lateral cavity-enhanced guided mode resonance structures for mid-wave infrared photodetector pixels

We present the design, fabrication, and optical characterization of ultra-compact mid-wave infrared photodetector pixels. Our design relies on a guided mode resonance structure to confine incident mid-infrared light to the 250 nm-thick absorber region of an all-epitaxially-grown material stack and a hybrid cavity-guided mode resonance to confine the mode in the lateral direction. The resulting pixel, with deep subwavelength thickness and lateral dimensions on the order of ∼2λ_o, is predicted to achieve external quantum efficiency of the order of 50%. Our work opens the door for truly compact mid-wave infrared pixels that offer the combined benefits of low dark current, room temperature operation, and small lateral size.