Distance sensitivity of thermal light second-order interference beyond spatial coherence

Abstract

We demonstrate the distance sensitivity of thermal light second-order interference beyond spatial coherence. This kind of interference, emerging from the measurement of the correlation between intensity fluctuations on two detectors, is sensitive to the distances separating a remote mask from the source and the detector, even when such information cannot be retrieved by first-order intensity measurements. We show how the sensitivity to such distances is intimately connected to the degree of correlation of the measured interference pattern in different experimental scenarios and independently of the spectral properties of light. Remarkably, in specific configurations, sensitivity to the distances of remote objects can be preserved even in the presence of turbulence. Unlike in previous schemes, such a distance sensitivity is reflected in the fundamental emergence of new critical parameters which benchmark the degree of second-order correlation, describing the counterintuitive emergence of spatial second-order interference not only in the absence of (first-order) coherence at both detectors but also when first-order interference is observed at one of the two detectors.

Comparative analysis of signal-to-noise ratio in correlation plenoptic imaging architectures

“…Plenoptic imaging is based on retrieving both spatial distribution and propagation direction of light within the single exposure of a digital camera [1][2][3]; this enables both refocusing in post-processing, and scanning-free 3D imaging. The technique is currently employed in several applications that include microscopy [4][5][6][7], particle image velocimetry [8], wavefront and remote sensing [9][10][11][12][13], particle tracking and sizing [14], and stereoscopy [1,15,16]. Being capable of acquiring multiple 2D viewpoints of the sample of interest within a single shot, plenoptic apparata are amongst the fastest devices for performing scanning-free 3D imaging [17], as already shown recently for surgical robotics [18], imaging of animal neuronal activity [7], blood-flow visualization [19], and endoscopy [20].…”