AJP SSN : 0971 – 3093
Vol 31, No 1, January, 2022

Asian

Journal of Physics

Volume 31 No 1 January 2022

A Special Issue in the Memory
of
Late Prof B N Gupta

Guest Edited By : R S Sirohi & A K Nirala

Anita Publications
FF-43, 1st Floor, Mangal Bazar, Laxmi Nagar, Delhi-110 092, India


On the methods to determine the focal length of an imaging system: A tutorial approach

Rajpal S Sirohi
Alabama A&M University Normal, Alabama, USA
This article is dedicated to late Prof B N Gupta


Focal length of an imaging system is an important parameter as it determines its gathering power, numerical aperture and resolution. Its determination becomes very difficult as one of the planes is not physically accessible. A number of methods have been developed that measure either the effective focal length or the back focal length. The objective of the present paper is to discuss various methods that have been investigated and reported in the literature. © Anita Publications. All rights reserved.

Keywords: Focal length, Radius of curvature, Nodal slide, Interferometry.


 

Collimation Methods

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Talbot Interferometry

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Lau Interferometry

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Moiré Deflectometry

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Shack-Hartmann Principle

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Interferometry

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Confocal

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Grating Diffraction

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Novel Methods

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