Design of Microlens Arrays for Thermal Imaging with Spintronic Poisson Bolometers

Abstract: Infrared (IR) detectors are widely used for their ability to sense thermal radiation. Recently, a room-temperature infrared detector known as the spintronic Poisson bolometer was introduced. Operating in a probabilistic regime governed by Poissonian counting statistics, it establishes a fundamentally different detection mechanism with the potential to relax conventional sensitivity limits. While offering fast digital readout, its sensitivity is currently limited by a small active area and array fill factor. In this work, we present design guidelines for spherical plano-convex microlens arrays that enhance light collection in spintronic Poisson bolometer arrays. Using FDTD simulations of aluminum oxide microlenses, we analyze focal properties, collection efficiency, and concentration factor in the mid-wave infrared (MWIR). A radiometric-stochastic model is used to quantify the resulting sensitivity improvements.