Nonredundant array of apertures to measure the spatial coherence in two dimensions with only one interferogram

Abstract

We propose to use a mask with a nonredundant array (NRA) of multiple apertures to measure spatial coherence in two dimensions. The spatial distribution of the apertures in the mask is made in such a way that we obtain a quasi-uniform sampling in the coherence domain. The spatial coherence is obtained by Fourier transform of the interferogram generated by the mask when it is illuminated by the light field under analysis.

Synthesis and characterization of complex partially coherent beams

“…Different techniques have been developed in the last decades [14][15][16][17][18][19][20][21][22][23] yet none has demonstrated to be feasible for quantitative estimation of the coherence properties of a general beam. Some methods assume certain hypothesis about light-field model, [14][15][16] its symmetry 17, 24 or coherence properties.…”

“…Some methods assume certain hypothesis about light-field model, [14][15][16] its symmetry 17, 24 or coherence properties. 22,25 Others apply pinhole or slit masks [20][21][22] which alter the measurements and decrease the signal to noise ratio caused by significant power reduction of the analyzed field. The phase-space tomography method 23 avoid this drawback.…”

Optical coherenscopy based on phase-space tomography

“…In the last decades, various methods have been proposed for MI or WD reconstruction [17][18][19][20][21][22][23][24][25][26], yet none has demonstrated to be feasible for quantitative estimation of the coherence state in the absence of a priori information. Some methods assume certain hypothesis about field model [18][19][20], its symmetry [17,21] or coherence homogeneity [22].…”

“…Some methods assume certain hypothesis about field model [18][19][20], its symmetry [17,21] or coherence homogeneity [22]. Others apply pinhole [23,24] or slit masks [25] which alter the measurements and decrease the signal to noise ratio caused by significant power reduction of the analyzed field. The phase-space tomography method [26], consisting of the WD reconstruction from its projections associated with intensity distributions, avoids these problems.…”

Measurement of spatial coherence through diffraction from a transparent mask with a phase discontinuity

“…Several interferometric techniques have been proposed for measuring spatial coherence, starting with Zernike's suggestion of using Young's two pinhole interferometer [1], although this requires varying the location of the pinholes over a large number of pairs of points. To overcome this drawback, alternative methods based on variants of Young's interferometer [2], nonredundant arrays of pinholes [3], and Sagnac interferometers [4,5] were proposed. Yet another approach, known as phase-space tomography [6][7][8], is based on measurements of the irradiance profile at a range of propagation distances.…”