Double-frequency grating shearing interferometer with built-in phase-shifting function for robust multi-level phase retrieval

Abstract

In this paper, we propose and demonstrate a novel interferometer and signal process to retrieve two-dimensional signals with multilevel phases. The interferometer is based on a shearing interferometry with double-frequency grating, and phase-shifting interferometry is derived as a built-in function of the lateral displacement of the grating. The interferometer not only retrieves the multilevel phase signals but also eliminates slow-varying phase errors wherever they occur. Owing to the common path algorithm, the new interferometer is more robust in dynamic circumstances for optical testing and data processing. We propose a pre-integral signal process for two-dimensional (2D) data processing to prevent post-phase-integral due to shearing interferometry. The simulation and experiment showed that the proposed interferometer with a pre-integral process has various advantages in signal processing for multilevel phase retrieval, and will be useful for higher data rates in optical data storage and free-space communication.

3-dimensional quantitative phase imaging and microscopy of bio and non-bio transparent phase samples using the radial shearing interferometric set-up

“…𝜀 𝑟 = 𝑒 −𝑖𝜃 ( 𝑐𝑜𝑠𝜃 𝑠𝑖𝑛𝜃 ) [6] The intensity 𝐼(𝜃) recorded on the CCD may therefore b e e x p r e s s e d a s ,…”

“…Compared to lateral shearing interferometry (LSI) [3] or advanced LSI [4] technique where shearing can be implemented in one direction at a time, RSI shearing is radial and therefore along all directions. Presently, with the enormous advancements in digital imaging and image processing, RSI, coupled with phase shifting techniques [5], [6], has emerged to be one of the most powerful techniques for quantitative wavefront evaluation along with 3dimensional imaging, and has seen various applications including testing of aspheric surfaces [7], [8] corneal topography measurement [9], [10], wavefront sensing in adaptive optics [11]- [14] and analysis of transient laser pulses [15].…”

Wire grid polarizer based in-line laser interferometer for macroscopic and microscopic phase estimation of transmissive and reflective phase samples

“…A lateral shear interferometer [42][43][44][45] or radial shear interferometer [46][47][48] along with a phase shifting technique could be the best solution for this kind of requirement, but the ultra-precision control in directional shift and complex calculation makes this technology far more error-prone. A near common-path laser interferometer and interference microscope design with polarization phase-shifting ability for reflective phase samples in converging illuminating beams has been previously proposed by the present authors [49][50][51].…”

Radial shearing interferometry with in-built polarization phase shifting for three-dimensional imaging and quantitative phase analysis of transparent phase objects in macro and microscopic order

“…Compared to lateral shearing interferometry (LSI) 3 or advanced LSI 4 technique where shearing can be implemented in one direction at a time, RSI shearing is radial and therefore along all directions. Presently, with the enormous advancements in digital image processing (DSP), RSI, coupled with phase shifting techniques [5][6][7] , has emerged to be one of the most powerful techniques for qualitative and quantitative wavefront evaluation along with 3-dimensional imaging and microscopy and has seen various applications including testing of aspheric surfaces 8,9 corneal topography measurement 10,11 , wavefront sensing in adaptive optics [12][13][14][15] and analysis of transient laser pulses 16 .…”