In this research a novel interferometric system is reported, which allows the generation of four simultaneous interferograms with phase shifts of π/2 The system consists of three coupled interferometers: a rectangular Sagnac interferometer which generates a primary pattern with crossed circular polarizations, coupled to two Michelson interferometers which operate as a multiplexing system, and generating replicas of the primary pattern The two coupled Michelson interferometers generate four patterns retaining their polarization properties, which allow independent phase shifts by placing a linear polarizer over each pattern, thereby, four interferograms with relative phase shifts of π/2 are obtained The optical phase is calculated using the well-known four-step algorithm With knowledge of the optical phase, different properties of the samples can be calculated or analyzed; in this case, by knowing the mean refractive index, we can calculate the mean thickness of test objects The results obtained for static transparent samples are presented The capability of the system to analyze dynamic events is shown when results for the calculation of a temperature field of a heat flow are presented

Measurement of mean thickness of transparent samples using simultaneous phase shifting interferometry with four interferograms.

For applications involving time varying optical phase distributions, fast cameras and/or pulsed lasers have to be used. To apply phase-shifting interferometry techniques (PSI) as well, single shot capture is required. Among others, modulation of polarization and phase grating interferometry is a possible technique to be considered. In this paper, a report about the use of this technique based on a double pulse laser system is presented. Single-pulse and twin-pulse operations are considered both in optical interferometers as well as in ESPI systems (mainly in subtraction mode). In ESPI a reduction of the degree of polarization appears due to scattering, so some measures have to be taken to prevent such deletereous effect. To show the feasibility of the proposed variants some experimental results are presented.

One-shot phase stepping with a pulsed laser and modulation of polarization: application to speckle interferometry.

Measurement of red blood cell characteristic using parallel phase shifting interferometry

We propose a general method of designing phase-analysis algorithms for Ronchi phase-shifting lateral-shearing interferometry. Based on the expression and method, three new phase-shifting algorithms are designed to eliminate negative error effects of interference from unwanted diffraction orders, which limits the accuracy of wavefront aberration measurement. The proposed eight-, 10-, and 13-frame algorithms can eliminate the effects of the first ±5, ±9, and ±15 multi-diffraction orders, respectively. Simulation works and experimental results verify the general expression and corresponding designed method.

Method for designing phase-retrieval algorithms for Ronchi phase-shifting lateral-shearing interferometry.

We report an optical implementation of a parallel phase-shifting quasi-common path interferometer using two modified Michelson interferometers to generate two interferograms. By using a displaceable polarizer’s array, placed on the image plane, we can obtain four phase-shifted interferograms in two captures. The system operates as a quasi-common path interferometer generating four beams, which are to interfere with alignment procedures on the mirrors of the Michelson configurations. The optical phase data are retrieved using the well-known four-step algorithms. To present the capabilities of the system, experimental results obtained from transparent structures are presented.

Optical path difference measurements with a two-step parallel phase shifting interferometer based on a modified Michelson configuration

Phase profile analysis of transparent objects through the use of a two windows interferometer based on a one beam splitter configuration

Diffraction theory of binary amplitude and phase gratings with applications for Ronchi test

Two-dimensional (2D) measurements were performed to examine the frequency dependence of the terahertz (THz) Kerr effect in diamond. Preliminary analysis shows evidence of frequency dependence.

J. A. Martínez Domínguez

Papers

Phase profile analysis of transparent objects through the use of a two windows interferometer based on a one beam splitter configuration

Diffraction theory of binary amplitude and phase gratings with applications for Ronchi test

Analysis of the Frequency Dependence of the Kerr Effect in Diamond using Two-Dimensional Spectroscopy