Computational Ghost Rotational Doppler Metrology

We present a scheme for measuring a rotational Doppler frequency shift with only a single-shot measurement. Our protocol benefits from the combination of computational temporal ghost imaging and heterodyne detection of the rotational Doppler effect. Specifically, by multiplexing a series of elaborately designed ring-shaped spatial patterns, we map the temporal rotational Doppler signal into the spatial domain and thus can collect the Doppler signal with a camera in a single-shot exposure. Then, by calculating intensity correlations between the resulting elaborate spatial patterns and the image captured by the camera, we reconstruct the temporal Doppler signal. In our experiments, we succeed in demonstrating fairly good performance for measuring the angular velocity of a real spinning object with a rough surface. Our scheme could find potential applications in remote sensing and could also inspire more attempts to develop protocols for temporal detection and processing on the basis of space-time duality.