Improved collimation testing using Talbot interferometry

Kothiyal, M. P.; Sirohi, R. S.

doi:10.1364/ao.26.004056

Cited by 66 publications

(17 citation statements)

References 4 publications

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“…Nevertheless, results are quite imprecise since the intensity distribution of the light beam usually changes as it propagates. More accurate beam collimation techniques based on different optical effects have been proposed such as those based on interferometry [1,2,3,4,5,6,7,8,9]. Selfimaging-based methods, also known as Talbot interferometry, use Talbot effect as a tool to create moiré fringes at the output of a double grating system where the second grating is placed at a self-image plane of the first one [10,11,12], z T = 2lp 2 /λ, where l is an integer, p is the period of the grating, and λ is the wavelength [13].…”

Section: Introductionmentioning

confidence: 99%

Dual self-image technique for beam collimation

Herrera-Fernandez

Sanchez‐Brea

Torcal-Milla

et al. 2016

J. Opt.

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Abstract. We propose an accurate technique for obtaining highly collimated beams, which also allows testing the collimation degree of a beam. It is based on comparing the period of two different self-images produced by a single diffraction grating. In this way, variations in the period of the diffraction grating do not affect to the measuring procedure. Self-images are acquired by two CMOS cameras and their periods are determined by fitting the variogram function of the self-images to a cosine function with polynomial envelopes. This way, loss of accuracy caused by imperfections of the measured self-images is avoided. As usual, collimation is obtained by displacing the collimation element with respect to the source along the optical axis. When the period of both self-images coincides, collimation is achieved. With this method neither a strict control of the period of the diffraction grating nor a transverse displacement, required in other techniques, are necessary. As an example, a LED considering paraxial approximation and point source illumination is collimated resulting a resolution in the divergence of the beam of δφ = ±1.57 µrad.

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Section: Introductionmentioning

confidence: 99%

Dual self-image technique for beam collimation

Herrera-Fernandez

Sanchez‐Brea

Torcal-Milla

et al. 2016

J. Opt.

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“…In past, several methods have been developed for checking the collimation of the optical beam. These methods are based on collimation testing using parallel plate shearing interferometry [1], Talbot interferometry [2][3][4], temporal coherence [5], wedge plate shearing interferometry [6], optically active mediums [7], Lau interferometry [8], double prism [9], etc. Among these techniques, the wedge plate shearing interferometric technique has been observed to have the best accuracy, is simple and can be realized with the help of compact geometry.…”

Section: Introductionmentioning

confidence: 99%

Collimation testing using wedge plate lateral shearing interferometry and Fourier fringe analysis

Dhanotia

Prakash

2011

Optics and Lasers in Engineering

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“…The judgment of effect of a general small angle on the moiré fringes is important for the accuracy of measurements based on moiré fringes, but these effects usually have not been considered, because in most applications the two grating planes are taken to be ideally parallel [1]. But in roll angle measurement based on moiré fringes, the two grating planes are not ideally parallel due to the pitch and yaw angle.…”

Section: Introductionmentioning

confidence: 99%