Phase shifting profilometry with optical vortices

Determination of microrelief of the sample by singular beams superposition

“…an experiment Due to its high sensitivity to wave front inhomogeneity, caused by geometry of the sample, optical vortices and their interference was adopted to surface roughness analysis and curvature imaging of reflecting surfaces [2,21]. Nevertheless, transparent samples with complex relief of boundary surface may have an inhomogeneity of refractivity index.…”

“…Another method named Optical Vortex Scanning Microscope for visualization and analysis of nanometer structures, where the sample is scanned by a moving vortex, was demonstrated in work [12]. Hence, the way of investigations the surface roughness and the thickness of the sample were demonstrated in work [21] by analyzing interference patterns in the form of a vortex spiral. The interference patters between reference beam and object vortex beam passing through the sample demonstrates rotation depending on surface parameters of the sample.…”

Deep-learning-based high-resolution recognition of rotating interference images in vortex beam interferometry

“…The recognition resolution for the 2D and 3D shape of optically transparent and reflecting surfaces could reach up to 5 nm with a wavelength of 632.8 nm. [9][10][11] Subsequently, an extensive research showed that PSI could be employed to estimate the refractive index from the rotation angle of the reconstructed vortex phase. 12 Meanwhile, Xu proposed and experimentally demonstrated vortex interferometry could be used for reliable characterization of phase properties introduced by meta-structures.…”

A high accuracy measurement method based on vortex polar axis rotation phase-shifting interferometry (VPAR-PSI)

“…Within the area of PSI, the swirl light beam may be created with a spatial light modulator (SLM), which operates at a very accurate stage shift [ [33] , [34] , [35] ]. With a coupling of scroll light beam phase displacement and phase unpacking technique, contactless, higher resolutions and a wider range of metrology solutions such as micro-deformations of materials, micro-displacement and optical device shapes can be realized [ 36 ]. There is a new methodology presented by Sun and others for the measurement of in-plane movements of bodies via the speckle interference principle by means of applying optical swirl phase transfers to spot measurements [ 37 ].…”