Dynamic phase imaging of microscopic measurements using parallel interferograms generated from a cyclic shear interferometer

Abstract

We present a technique which allows us to generate two parallel interferograms with phase shifts of π/2 using a Cyclic Shear Interferometer (CSI) and a polarizing splitter. Because of the use of a CSI, we obtain the derivative phase data map directly, due to its configuration, it is immune to vibrations because the reference wavefront and the object wavefront have a common path; the shearing interferometer is insensitive to temperature and vibration. To obtain the optical phase data map, two interferograms are generated by collocating a polarizing device at the output of the CSI. The optical phase was processed using a Vargas-Quiroga algorithm. Related experimental results obtained for dynamic microscopic transparent samples are presented.

Robust two-step phase estimation using the Simplified Lissajous Ellipse Fitting method with Gabor Filters Bank preprocessing

“…It is important to note that the high amount of harmonics in Figure 9h is due to used phase extraction equation which includes a piston term, in this case Eq. (7). If the phase was recovered by (28), the MAE would be reduced as presented in Figure 9l.…”

“…Even though the calculation can be performed in a single shot [4], the use of several phase shifted interferograms proved to make the measurement more robust to environmental variations [5]. Nowadays, the tendency has been to reduce the number of steps in order to measure dynamic events [6][7][8][9][10][11][12].…”

“…The spatial and temporal dependency of the background intensity, the amplitude modulation and noise are common in non-aligned arrangements [1]. These issues also apply to one-shot interferometry, where the use of optical components such as diffractive devices, polarizers or pixelated masks disturb the captured interferograms [6][7][8][9].…”

“…Real component of the GFs corresponding to the first orientations and periods equal to[7,10,15,25] pixels, respectively.…”

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

“…The polarization filters angles are: 1 = 0 • , 2 = 45 • , 3 = 90 • and 4 = 135 • , and each one of them represents phase shifts of 0, /2, and 3 /2 respectively. To minimize errors in amplitude generated by the placement of polarizers at different angles [7,8], every interferogram used was subjected to a rescaling and normalization process, using digital image processing techniques [9,10]. This procedure generates patterns of equal intensities.…”