Sensitive infrared signal detection by upconversion technique

Abstract

We demonstrated upconversion assisted detection of a 2.05-μm signal by sum frequency generation to generate a 700-nm light using a bulk periodically poled lithium niobate crystal. The achieved 94% intrinsic upconversion efficiency and 22.58% overall detection efficiency at a pW level of 2.05 μm pave the path to detect extremely weak infrared (IR) signals for remote sensing applications.