Kuppuswamy Venkatesan Sriram

Direct determination of focal length by using Talbot interferometry

A new and simple technique for the determination of the focal length of positive lenses and concave spherical surfaces by Talbot interferometry is described. Results of measurements are presented. We show that high measurement accuracy can be achieved with this technique.

Talbot interferometry in noncollimated illumination for curvature and focal length measurements

We describe a simple method for measuring the radius of curvature by using Talbot interferometry in a noncollimated light beam. This scheme can also be used to determine the focal length of the collimating lens employed in the setup. Results of the measurements are presented. A discussion of achievable accuracies and the proper choice of parameters is included.

Setting sensitivity in Talbot interferometry with modified gratings

Abstract A dual field grating has been introduced for use in Talbot interferometry. We report here results of an experimental investigation on setting sensitivity when using these gratings for testing.

Double-wedge-plate interferometer for collimation testing : new configurations

Some new configurations of a wedge-plate interferometer are described that use two wedge plates for collimation testing with a built-in reference unlike a single wedge plate for which an external reference is required. Theory and measurement results are presented.

Collimation testing with linear dual-field, spiral, and evolute gratings: a comparative study.

A comparative study of the performance of linear dual-field, spiral, and evolute gratings for collimation testing with Talbot interferometry is reported.

Curvature and focal length measurements using compensation of a collimated beam

Abstract A simple method for measuring the radius of curvature of a spherical surface using compensation of a collimated beam is described. The same method can also be used for the determination of the focal length of the collimating lens employed. Results of the measurements using this technique are presented. Investigations on the achievable accuracies and the proper choice of parameters are carried out and the results discussed.

Modified double-wedge-plate shearing interferometer for collimation testing

A modified configuration of the double-wedge-plate shearing interferometer for collimation testing is described. Results of the measurements to determine the setting sensitivity with this configuration are presented.

Array generation using double wedge plate interferometer

Abstract Arrays of equal intensity spots are usually realized by specially designed phase gratings, spatial filtering, wavefront division using holographic lenslets and the Talbot effect. In this paper, a new method of generating arrays is described where two wedge plates are used in a new configuration.

Multiple-beam wedge-plate shear interferometer for collimation testing

We describe a modification of the wedge-plate shear interferometer for collimation testing. The surface of the wedge plate is coated to increase the reflectivity such that multiple-beam interference takes place resulting in sharp fringes. In addition to sharpening the fringes also tend to split when the test beam is noncollimated. This splitting has been used as a test criterion for collimation testing. Experimental results are presented.

Evaluation of phase conjugated beams using Talbot interferometry

Abstract A new technique of evaluating phase conjugated beams using a moire technique based on Talbot interferometry with dual-field linear gratings is proposed. The quantitative assessment of phase conjugated beam is done and the advantages of this technique are discussed.