Coherence Measurements Of Scattered Incoherent Light For Lensless Identification Of An Object'S Location And Size

Abstract

In the absence of a lens to form an image, incoherent or partially coherent light scattering o- an obstructive or reflective object forms a broad intensity distribution in the far field with only feeble spatial features. We show here that measuring the complex spatial coherence function can help in the identification of the size and location of a one-dimensional object placed in the path of a partially coherent light source. The complex coherence function is measured in the far field through wavefront sampling, which is performed via dynamically reconfigurable slits implemented on a digital micromirror device (DMD). The impact of an object - parameterized by size and location - that either intercepts or reflects incoherent light is studied. The experimental results show that measuring the spatial coherence function as a function of the separation between two slits located symmetrically around the optical axis can identify the object transverse location and angle subtended from the detection plane (the ratio of the object width to the axial distance from the detector). The measurements are in good agreement with numerical simulations of a forward model based on Fresnel propagators. The rapid refresh rate of DMDs may enable real-time operation of such a lensless coherency imaging scheme.

Publication Date

6-12-2017

Publication Title

Optics Express

Volume

25

Issue

12

Number of Pages

13087-13100

Document Type

Article

Personal Identifier

scopus

DOI Link

https://doi.org/10.1364/OE.25.013087

Socpus ID

85020714685 (Scopus)

Source API URL

https://api.elsevier.com/content/abstract/scopus_id/85020714685

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