Direct defocus measurement using single astigmatic lens: a theoretical study

Santanu Konwar; Nagendra Kumar; S. S. Goutam Buddha

doi:10.1117/12.2649501

8 March 2023 Direct defocus measurement using single astigmatic lens: a theoretical study

Santanu Konwar, Nagendra Kumar, S. S. Goutam Buddha

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Proceedings Volume 12428, Photonic Instrumentation Engineering X; 1242812 (2023) https://doi.org/10.1117/12.2649501
Event: SPIE OPTO, 2023, San Francisco, California, United States

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Abstract

Astigmatism has a very unique ability to change the shape of the intensity profile of an optical beam as we move away on either side of the focal plane of the optical system. This property of astigmatism can be used to measure the focussing error or the amplitude of defocus present at the plane of measurement. The use of astigmatism to measure focussing error is a very simple and easily implementable process. Astigmatism can be introduced with the help of an astigmatic lens. The approach provides a direct measure of the amplitude of defocus present in an optical beam from the measure of the intensity at the focal plane. In this paper we put forward a theoretical discussion on the above mentioned approach.

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Santanu Konwar, Nagendra Kumar, and S. S. Goutam Buddha "Direct defocus measurement using single astigmatic lens: a theoretical study", Proc. SPIE 12428, Photonic Instrumentation Engineering X, 1242812 (8 March 2023); https://doi.org/10.1117/12.2649501

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