3D and hyperspectral imaging through photon correlation and coherence of light

Photon correlation imaging has emerged as a powerful framework for overcoming the fundamental limitations of conventional optical systems. While initially explored in the quantum domain using entangled photons, similar performance can be achieved with thermal or pseudo-thermal light, thanks to the spatial coherence inherent in such sources. Correlation plenoptic imaging (CPI) leverages this principle to perform high-resolution, scan-free volumetric imaging by measuring second-order correlations between two spatially resolving detectors. Unlike standard light-field imaging, CPI avoids resolution trade-offs imposed by microlens arrays and achieves diffraction-limited performance even with low numerical apertures. Recent theoretical developments have clarified that the imaging capabilities of CPI originate not from photon correlation itself, but from the analytical form of the measured correlation function-essentially a coherent diffraction pattern. This insight has led to the implementation of analogous systems using standard optics illuminated by structured, spatially coherent light, enabling real-time direct 3D imaging through programmable illumination arrays. Building on these results, correlation hyperspectral imaging (CHI) has been introduced as a new technique that couples a conventional imaging system with a spectrometer through intensity correlation measurements. CHI enables diffraction-limited hyperspectral imaging without scanning, offering independent control of spatial and spectral resolution. Ongoing research explores the integration of CHI and CPI into a single device, capable of acquiring fully three-dimensional, spectrally resolved datacubes in a passive and mechanically stable configuration. Such a system promises broad impact across microscopy, materials analysis, and remote sensing.