Exploration for adequate non-diffractive beam generation in dense scattering media

Abstract

The propagation methods of a non-diffractive beam (NDB) for optical sensing in scattering media have been extensively studied. However, those methods can realize the high resolution and long depth of focus in the viewpoint of microscopic imaging. In this study, we focus on macroscopic sensing in living tissues with a depth of a few tens centimeters. An experimental approach for generating adequate NDB in dense scattering media based on the linear relationship between propagation distance and transport mean free path is reported. For annular beams with different diameters, the same changes of the center intensity ratio of NDB are obtained from the experiment results. They are discussed with theoretical analysis. As a result, the maximum center intensity ratio of the adequate generated NDB can be estimated at arbitrary propagation distance in the dense scattering media.

The Arago–Poisson Spot: New Applications for an Old Concept

“…It has also been shown to propagate faster than light [6][7][8][9]. Usually, it propagates in a quasi non-diffracting way [10], and its size should decrease when it moves closer to the disk [11]. The appearance of the spot is not limited to optics and has also been observed for X-rays [12], in acoustics [13], for gravitational waves [14], and even with particles such as molecules [15,16].…”