Carrier fringes and a non-conventional rotational shear in a triangular cyclic-path interferometer (original) (raw)
Related papers
Wavefront recovery Fourier-based algorithm used in a vectorial shearing interferometer
SPIE Proceedings, 2013
ABSTRACT Vectorial Shearing Interferometer is able to select variable shear and tilt along any wavefront direction. This system is self-referenced and with variable sensibility. We proposed this instrument to measure a phase object without rotational symmetry. Phase recovery is implemented by a Fourier-based algorithm and spatial unwrapping methods. We show results emphasizing the advantage in the easier selection of fringe density and directional derivative orientation for a speci c optical element.
Optics Express, 2014
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.
Reversal and rotationally shearing interferometer
Optics Communications, 2004
We describe and demonstrate experimentally a compact, aberration-selective, reversal interferometer with variable rotational shearing of wave front. It is constructed with only two beam-splitter cubes, each one with one face aluminized, cemented together, and mounted in a rotary holder. This interferometer is quite insensitive to vibrations, because the wave fronts pass only through the cemented cubes to generate the interference pattern. All the rotationally symmetric aberrations are removed and the asymmetrical ones can be selectively isolated with an appropriate rotation of the cubes. The variable shearing angle is shown to control the sensitivity for detection of rotationally asymmetric aberrations like coma and tilt. The principle of operation of the interferometer is described, and its performance is analyzed.
A single-shot common-path phase-stepping radial shearing interferometer for wavefront measurements
Optics Express, 2011
A single-shot common-path phase-stepping radial shearing interferometer (RSI) is proposed for wavefront measurements. In the proposed RSI, three quarter-wave plates are used as phase shifters to produce four spatially separated phase-stepping fringe patterns that are recorded simultaneously by a single CCD camera. The proposed RSI can measure the wavefront under test in real-time, and it is also insensitive to environmental vibration due to its common-path structure. Experimentally the proposed RSI is applied to detect the distorted wavefronts generated by a liquid crystal spatial light modulator. The measured aberrations are in good agreement with that obtained with (by) a Hartmann-Shack wavefront sensor, indicating that the proposed RSI is a useful tool for wavefront measurements.
Shifting of Localization Planes in Optical Testing: Application to a Shearing Interferometer
Applied Optics, 2001
An amplitude-division two-beam interferometer illuminated by a quasi-monochromatic, spatially incoherent, and periodic source yields multiple localization planes of interference fringes. If a thick transmission sample with a few localized phase disturbances in various layers is placed in the interferometer, the disturbances in a layer can be detected, making its images through the two arms coincide with a chosen localization plane. Different layers can be analyzed by means of shifting the localization plane by a variation of the source period without any other changes in the device. Here we illustrate this method by applying it to a shearing interferometer, a classical Wollaston prism placed between crossed polarizers. Experimental images of different observation planes are obtained, and they are in good agreement with the theoretical expectations.
Electronic shear interferometry: application of a (double-) pulsed laser
Applied Optics, 1993
The use of a double-pulsed laser in interferometric metrology relaxes the stability requirements for the experimental setup. The use of such a laser also makes it possible for one to study high-speed dynamic processes. We justify the use of a double-pulsed laser in electronic shear interferometry. We show how image subtraction can be applied to produce high-quality fringe patterns without a special aperture design. The fringe visibility is studied theoretically and is compared with the fringe visibility obtained when the closely related television-holography technique is used. The new double-pulse subtraction technique offers the possibility of compensation for laser intensity fluctuations that can affect the fringe visibility significantly in pulsed electronic shear interferometry.
A single-shot phase-shifting radial-shearing interferometer
Journal of Optics A: Pure and Applied Optics, 2009
A grating interferometer to simultaneously produce n radial-sheared phase-shifted interferograms is proposed. It consists basically of an adaptation of a well known radial-shear interferometer in conjunction with a grating interferometer. This combination enables the use of phase-shifting techniques for measuring phase distributions. Several interferograms can be achieved with a double phase grating of a given frequency, and the required phase shift can be performed with modulation of polarization. Experimental results are presented for cases of n = 4, 5, and 7 interferograms. These results are obtained with two configurations of the system, which are discussed.
Optical Engineering, 2007
An original experimental setup for shearography with metrological applications is presented. The simplicity and the efficiency of the setup are provided by a shearing device, a prism that separates the TE and TM polarization modes with a coating and a thin glass plate placed on its face. The use of this shearing device enables an in-line and almost-common path configuration for the shearing interferometer, a path that leads to high stability and a low sensitivity to external disturbances. Moreover, the sensitivity of the interferometer can be easily adjusted for different applications by varying the shearing amount with glass plates of different thicknesses or by moving the shearing device between two lenses along the optical axis. The temporal phase-shifting method is applied through the use of a liquid crystal variable retarder.