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Sanjib Chatterjee

Bio: Sanjib Chatterjee is an academic researcher from Raja Ramanna Centre for Advanced Technology. The author has contributed to research in topics: Interferometry & Wavefront. The author has an hindex of 9, co-authored 46 publications receiving 262 citations. Previous affiliations of Sanjib Chatterjee include Indian Department of Atomic Energy.

Papers
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Journal ArticleDOI
TL;DR: A new technique for the simultaneous measurement of refractive index and wedge angle of optical windows using Fizeau interferometry and a cyclic path optical configuration (CPOC).
Abstract: We present a new technique for the simultaneous measurement of refractive index and wedge angle of optical windows using Fizeau interferometry and a cyclic path optical configuration (CPOC). Two laterally separated beams are obtained from an expanded collimated beam using an aperture containing two rectangular openings. The test wedge plate is placed in one of the two separated beams. Using CPOC, these two beams are made to overlap and interfere, producing interference fringes in the overlapping region. The beams reflected from the front and back surfaces of the test wedge plate interfere and produce Fizeau fringes. The refractive index is related to the spacing of the above two beam fringes. The wedge angle is determined from the evaluated values of the refractive index and Fizeau fringe spacing. The results obtained for a BK-7 optical window are presented.

14 citations

Journal ArticleDOI
TL;DR: In this paper, a technique for determination of residual wedge angle of high optical quality transparent parallel plate using a reversal shear interferometer-based optical system has been discussed, in which the parallel plate to be tested is used to introduce angular tilt in the preset two-beam interference fringes of a reversal Shear Interferometer.
Abstract: A technique for determination of residual wedge angle of high optical quality transparent parallel plate using a reversal shear interferometer-based optical system has been discussed. In this technique the parallel plate to be tested is used to introduce angular tilt in the preset two-beam interference fringes of a reversal shear interferometer. The parallelism is calculated from the angular tilt of the fringes. The technique is more sensitive compared to techniques using Fizeau interferometer and is most suitable for highly parallel transparent plate with very low residual wedge angle.

13 citations

Journal ArticleDOI
TL;DR: A new technique for the measurement of two-dimensional small angular deviation is presented and a monolithic prism interferometer, which is practically insensitive to vibration, is also proposed.
Abstract: A new technique for the measurement of two-dimensional small angular deviation is presented. A compound prism, which effectively produces a combination of two right-angled prisms in orthogonal directions, and plane reference surfaces have been utilized for the measurement of the orthogonal components of the angular tilt of an incident plane wavefront. Each orthogonal component of the angular tilt is separately measured from the angular rotation of the resultant wedge fringes between two plane wavefronts generated due to splitting of the incident plane wavefront by the corresponding set of right-angled prism and plane reference surface. The technique is shown to have high sensitivity for the measurement of small angle deviation. A monolithic prism interferometer, which is practically insensitive to vibration, is also proposed. Results obtained for the measurement of a known tilt angle are presented.

10 citations

Journal ArticleDOI
TL;DR: In this article, a technique for determination of the thickness of a plane-parallel transparent plate using a lateral shearing interferometer (LSI) is discussed. But this technique is limited to the case where a corrected lens focuses an expanded collimated laser beam on the surface of the plane mirror placed at the back focal plane of the lens.
Abstract: A technique for determination of the thickness of a plane-parallel transparent plate using a lateral shearing interferometer (LSI) is discussed. With this technique, the parallel plate whose thickness is to be determined is used to introduce a change in the collimation of the retro-reflected beam from an optical setup in which a corrected lens focuses an expanded collimated laser beam on the surface of a plane mirror placed at the back focal plane of the lens. The thickness of the plate is calculated by measuring the defocusing caused by the plate, which is inserted in the beam path between the collimating lens and the plane mirror, with an LSI. Results obtained for a parallel plate are presented.

10 citations

Journal ArticleDOI
TL;DR: The results of the development of a much simpler optical configuration for the long-trace profiler (LTP) are presented, which employs a cyclic optical configuration to achieve zero optical path difference for the closely spaced, laterally separated laser beams.
Abstract: The results of the development of a much simpler optical configuration for the long-trace profiler (LTP) are presented. The current technique employs a cyclic optical configuration to achieve zero optical path difference for the closely spaced, laterally separated laser beams. The accuracy of measurement is found to remain as good as that in the case of the widely used LTP, although the geometrical alignment problem is simplified significantly.

9 citations


Cited by
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Journal Article
TL;DR: In this paper, the first observation of interference in the light scattered from two trapped atoms localized in a linear Paul trap was reported, and the visibility of the interference fringes can be explained in the frame-work of Bragg scattering by a harmonic crystal, but with important differences compared to the case of a large crystal.
Abstract: We report the first observation of interference in the light scattered from two trapped atoms ({sup 198}Hg{sup +} ions localized in a linear Paul trap). The visibility of the interference fringes can be explained in the frame-work of Bragg scattering by a harmonic crystal, but with important differences compared to the case of a large crystal. Comparison of the experimental data with theory shows that the interference pattern offers another method to determine ion temperatures and separations. Furthermore, by exploiting the atom`s internal structure we have found a way to obtain {open_quotes}which path{close_quotes} information without invoking the position-momentum uncertainty relation. If the light scattered by the atoms is detected in a polarization-sensitive way, then it is possible to selectively demonstrate either the particle-nature or the wave-nature of the scattered photons.

190 citations

Journal ArticleDOI
TL;DR: In this paper, the focal length and the depth of focus of the axicon lens of a polymeric microaxicon were measured, and the full width at half maximum of the beam was obtained.
Abstract: We present a quick, simple and accurate digital holographic characterization of the Bessel beams produced by polymeric microaxicons. This technique allows the numerical reconstruction of both intensity and phase of the beam at whichever point starting from a single acquired hologram. From these data, it is possible to go back to the axicon structure, and to gather information about their characteristics. In particular, the focal length and the depth of focus of the axicon lens are experimentally measured, and the full width at half maximum of the beam is obtained too. The depth of focus, very large for a Bessel beam with respect to a Gaussian one, is successfully exploited for optical trapping of micrometric objects.

49 citations

Journal ArticleDOI
TL;DR: A new laser differential reflection-confocal focal-length measurement (DRCFM) method has high accuracy and strong anti-interference capability and theoretical analyses and experimental results indicate that the DRCFM relative measurement error is less than 10 ppm.
Abstract: A new laser differential reflection-confocal focal-length measurement (DRCFM) method is proposed for the high-accuracy measurement of the lens focal length. DRCFM uses weak light reflected from the lens last surface to determine the vertex position of this surface. Differential confocal technology is then used to identify precisely the lens focus and vertex of the lens last surface, thereby enabling the precise measurement of the lens focal length. Compared with existing measurement methods, DRCFM has high accuracy and strong anti-interference capability. Theoretical analyses and experimental results indicate that the DRCFM relative measurement error is less than 10 ppm.

37 citations

Journal ArticleDOI
TL;DR: A compact, fiber-coupled, six degree-of-freedom measurement system which enables fast, accurate calibration, and error mapping of precision linear stages is presented and has the advantages of simplicity, compactness, and relatively low cost.
Abstract: A compact, fiber-coupled, six degree-of-freedom measurement system which enables fast, accurate calibration, and error mapping of precision linear stages is presented. The novel design has the advantages of simplicity, compactness, and relatively low cost. This proposed sensor can simultaneously measure displacement, two straightness errors, and changes in pitch, yaw, and roll using a single optical beam traveling between the measurement system and a small target. The optical configuration of the system and the working principle for all degrees-of-freedom are presented along with the influence and compensation of crosstalk motions in roll and straightness measurements. Several comparison experiments are conducted to investigate the feasibility and performance of the proposed system in each degree-of-freedom independently. Comparison experiments to a commercial interferometer demonstrate error standard deviations of 0.33 μm in straightness, 0.14 μrad in pitch, 0.44 μradin yaw, and 45.8 μrad in roll.

29 citations

Journal ArticleDOI
TL;DR: A ring-shaped random laser in momentum space is designed by directly coupling a random laser with a commercial optical fiber, which is an excellent illuminating source for high-quality imaging with an extremely low speckle noise and may promote the practical applications of random lasers in the fields of sensing, in vivo biological imaging, and high brightness full-field illumination.
Abstract: A ring-shaped random laser in momentum space is designed by directly coupling a random laser with a commercial optical fiber. By using a simple approach of selectively coating the random gain layer on the surface of the fiber, red and yellow random lasers are respectively achieved with low threshold values and a good emission direction due to the guiding role of optical fibers. The unique coupling mechanism leads to a random laser with a ring shape in momentum space, which is an excellent illuminating source for high-quality imaging with an extremely low speckle noise. More importantly, a triple-state color-switchable random laser with yellow, red and yellow-red dual-colors can be flexible, and is obtained by simply moving the pump position. The results may promote the practical applications of random lasers in the fields of sensing, in vivo biological imaging, and high brightness full-field illumination.

27 citations