Single-shot time-of-flight ranging with sub-wavelength accuracy using vortex beam

Time-of-flight (TOF) ranging has been widely used for accurate measurement in science and industry. Existing TOF schemes implemented in the time or frequency domain require continuous measurements to achieve high accuracy. However, the minimum acquisition time for continuous measurement limited the improvement of the acquisition rate. Here, we show that vortex beams provide a route to transfer TOF into the rotation of the spatial intensity distribution of light which can be detected in a single-shot manner. This mechanism enables ranging systems with acquisition rates exceeding one gigahertz and sub-wavelength accuracy. We demonstrate single-shot depth measurements with an accuracy of 51 nanometers, allowing for ultrafast acquisition of displacement in one nanosecond with the same accuracy. These results open up the possibility of improving acquisition rate and accuracy independently through measurement in the space domain.