Intensity correlations of light waves scattered by random media having parity-time symmetry

Light waves scattered by random media with parity-time (PT) symmetry exhibit unique second-order statistical characteristics in the far field [Phys. Rev. A 105, 023510 (2022)]; however, the nature of its higher-order statistics remains unexplored. This paper aims to analyze the intensity correlation (IC), i.e., fourth-order statistics, of a normally incident plane wave scattered by PT-symmetric random media. By utilizing the first-order Born approximation, we analytically show that this type of PT symmetry causes the spatial profile of the IC function of scattered light to split into three parts in the far zone. Moreover, this IC profile rotates with respect to its reference spatial point as the gain and loss of scatterers vary. These findings suggest an effective approach to detect the random medium's gain or loss properties by measuring the IC distribution of scattered light in the far zone. (c) 2024 Optica Publishing Group. All rights, including for text and data mining (TDM), Artificial Intelligence (AI) training, and similar technologies, are reserved.