High-frequency demodulation of wide-area optical signals in a snapshot manner remains a technological challenge. This paper presents a snapshot quadrature demodulation imaging technique capable of estimating amplitude and phase from a single acquisition, without emitter-receiver synchronization, and with continuous frequency tuning. An all-optical setup uses an electro-optic crystal as a fast sinusoidal optical transmission gate, allowing simultaneous recording of four quadrature image channels. The technique enables snapshot demodulation of images with good spatial resolution and continuous frequency selectivity up to several hundred kilohertz.

Swapnesh Panigrahi, Julien Fade, Romain Agaisse, Hema Ramachandran, Mehdi Alouini