Phasor field waves: experimental demonstrations of wave-like properties.

Abstract

Time-of-flight (ToF) non-line-of-sight (NLoS) imaging reconstructs images of scenes with light that have undergone diffuse reflections. While, in the past, ToF light propagation and reconstruction methods have been described using their own inverse methods, it has recently been shown that ToF light transport can be described as the propagation of a wave, allowing it to be modeled by the same methods that are applied for direct imaging with electromagnetic or sound waves. This wave of fluctuating optical irradiance is called the phasor field (P-field) wave. Here, we perform a series of experiments to show the wave-like behavior of this P-field wave. We design a P-field source and detector and use them to demonstrate interference of P-field waves in a double slit experiment, as well as mutually-independent focusing and imaging of P-field waves and their optical carrier. Besides establishing the properties of P-field waves, our work demonstrates that imaging of ToF signals is possible without any computation enabling fast and energy-efficient NLoS imaging systems.