Generation and evolution of vortex array with variable-ratio lateral-shearing interferometry

Abstract

Different from the method by plane-wave interference, here an efficient approach is proposed to generate optical vortex array (VA) based on lateral-shearing interferometer (LSI), in which the evolution from light spot array to VA can be observed by continuously variable shear ratio in a certain range. VAs with topological charge 2 and 1 are simulated by software GLAD and proved to be effectiveness through optical experiment. Theoretical analysis and experimental results show that when the shear ratio approaches to zero, we can stably obtain a vortex array with high density and variable topological charge.

Wavefront Microscopy Using Quadriwave Lateral Shearing Interferometry: From Bioimaging to Nanophotonics

“…While the QLSI pattern of the cross-grating remains the most popular option, variations of this cross-grating have been used, with 3-fold or 4-fold symmetries, with different designs of the unit cell − or a binary random mask . A recent study even demonstrated the possibility of using a nonperiodic optical element, simply consisting of a thin diffuser, which creates a speckle-like pattern on the camera.…”

Cross-grating phase microscopy (CGM): In silico experiment (insilex) algorithm, noise and accuracy

“…In this article, we focus on the cross-grating used in QLSI, with a grexel characterized by a checkerboard pattern of 0 and 𝜋 phase shifts. The grexel pattern of QLSI remained mostly unchanged for 20 years, except in few articles [32][33][34][35]37].…”

“…In practice, to compensate for any imperfection of the incoming planar wavefront, a reference interferogram is recorded first, without the object of interest in the field of view, from which a reference OPD is calculated and subtracted from all subsequent images of interest. Different types of cross-gratings have been used in CGM, with 3fold or 4-fold symmetries [31], with different designs of the unit cell [32][33][34][35], or even with a thin (non-periodic) diffuser [36] or a binary random mask [37]. In the context of optical microscopy, the main instance of CGM that has been used so far is quadriwave lateral shearing interferometry (QLSI) [13,14,31].…”

Cross-grating phase microscopy (CGM): In-silico experiment (insilex) algorithm, noise and accuracy

“…where h is the thickness profile of the object, n the refractive index of the object and n 0 the refractive index of the environment. Different types of cross-gratings have been used in CGM, with 3-fold or 4-fold symmetries [30], with different designs of the unit cell [31][32][33][34], or even with a thin (non-periodic) diffuser [35] or a binary random mask. [36] In the context of optical microscopy, the main instance of CGM that has been used so far is quadriwave lateral shearing interferometry (QLSI) [13,14,30].…”

“…The grexel pattern of QLSI remained mostly unchanged for 20 years, except in a couple of articles. [31][32][33][34]36] • Λ and Z. Λ is the grexel lateral size, or equivalently the grating period. It is not a parameter that can be continuously modified experimentally, hence the interest of conducting in silico experiments.…”