David-Ignacio Serrano-García

Bio: David-Ignacio Serrano-García is an academic researcher from Centro de Investigaciones en Optica. The author has contributed to research in topics: Phase (waves) & Interferometry. The author has an hindex of 2, co-authored 9 publications receiving 31 citations. Previous affiliations of David-Ignacio Serrano-García include Utsunomiya University.

Parallel two-step phase shifting interferometry using a double cyclic shear interferometer

Abstract: A parallel two-step polarizing phase shifting interferometer based on a Double Cyclic Shear Interferometer (DCSI) is proposed in this paper for quantitative phase imaging. The system has the advantage of retrieving the derivative phase data map directly. Due to its configuration, it presents better stability against external configurations than other types of interferometers. The DCSI generates two π-shifted interferograms, which are recorded by the CCD camera in a single-shot. The separation between parallel interferograms can be varied in the two axes for convenience. To obtain the optical phase data map, a parallel phase shift between interferograms is obtained by rotating a half wave plate retarder. We analyzed the cases of four patterns with shifts of π/2 captured in two shots; the optical phase was processed by a four-step algorithm. Related experimental results obtained for microscopic transparent samples are presented.

Adjustable-window grating interferometer based on a Mach-Zehnder configuration for phase profile measurements of transparent samples

Abstract: This communication describes some details of polarization modulation that are useful in phase-shifting interferometry when applied to phase profile measurements of phase objects. Since non-destructive optical techniques allow surface measurement with high accuracy, a Mach-Zehnder configuration coupled to a 4-f arrangement using phase gratings placed on the Fourier plane was implemented to analyze phase objects. Each beam of the interferometer goes through a birefringent wave plate in order to achieve nearly circular polarization of opposite rotations, with respect to each other. The interference of the fields associated with replicated beams, centered on each diffraction order, is achieved varying the spacing of windows with respect to the grating period. Experimental results are presented for cases of four and nine simultaneously captured interferograms.

Slope measurement of a phase object

Abstract: An interferometric method to measure the slope of phase objects is presented. The analysis was performed by implementing of a polarizing phase shifting cyclic shear interferometer coupled to a grating interferometer. This system can obtain four interference patterns with adjustable phase shifts and variable lateral shear. In order to extract the slope of a phase object, is analyzed the optical phase applying the classical method of phase extraction.

Single shot phase shifting techniques for 4D radial slope measurements of transparent samples

Abstract: Through the use of non-destructive optical techniques to measure surfaces with high accuracy, a Mach-Zehnder Radial-Shear interferometer (MZRI) was implemented to analyze the radial slope of phase objects using simultaneous phase-shifting interferometry (SPSI). This optical configuration allows one to simultaneously obtain n-shearograms in order to retrieve the optical phase data map with higher accuracy. Phase reconstruction is performed using a well-known four step phase shifting algorithm. The experimental results for transparent samples are presented in this paper.

Experimental π Phase-Shifts Observed in the Fourier Spectra of Phase Gratings and Applications in Simultaneous PSI

Abstract: As it is very well known, the Fourier coefficients of only-phase gratings are integer order Bessel functions of the first kind. The values of these real-valued functions oscillate around zero, so they can adopt negative values, thereby introducing phase shifts of π at certain diffraction orders. Because of this, an almost trivial fact seems to have been overlooked in the literature regarding its practical implications.

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

Abstract: 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

4D measurements of biological and synthetic structures using a dynamic interferometer

Abstract: Considering the deficiency of time elapsed for phase-stepping interferometric techniques and the need of developing non-contact and on-line measurement with high accuracy, a single-shot phase-shifting triple-interferometer (PSTI) is developed for analysis of characteristics of transparent structures and optical path difference (OPD) measurements. In the proposed PSTI, coupled three interferometers which generate four interference patterns, and a polarizer array is used as phase shifters to produce four spatially separated interferograms with π/2-phase shifts, which are recorded in a single capture by a camera. The configuration of the PSTI allows dynamic measurements (4D measurements) and does not require vibration isolation. We have applied the developed system to examine the size and OPD of cells, and the slope of thin films

Phase-shifting infrared digital holographic microscopy based on an all-fiber variable phase shifter.

Abstract: Phase-shifting infrared digital holographic microscopy based on a homemade all-fiber variable phase shifter is presented to quantitatively obtain the phase distribution of an object wave carrying the information of a transparent specimen in the infrared band. The all-fiber variable phase shifter, which consists of a tubular piezoelectric transducer (PZT) and a single-mode fiber, can accurately produce any phase shift between 0 and 2π by modulating the driving voltage of the tubular PZT. Taking measurements of different staircase structures on a silicon wafer as samples, two configurations are presented based on different phase-shifting implementations: one is a slight off-axis two-step phase shift and the other is an in-line four-step phase shift. The reconstructed results prove the validity of this method.

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

Abstract: 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.