Theory of parametric upconversion of thermal images

Abstract

This paper extends the theory of parametric upconversion to describe the detection of a thermal image via sum‐frequency generation. The theory developed describes the power output, resolution, contrast and spectral bandwidth to be expected from a thermal upconverter. It is shown that current technology is adequate for upconversion of a 100‐resolution‐element high‐contrast thermal scene. Difficulties preventing detection of a near‐room‐temperature low‐resolution scene are discussed.