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Optical Engineering

Focal length measurement of microlens array for Shack–Hartmann wavefront sensor using interferometer
Author(s): M. Senthil Kumar; Chittur S. Narayanamurthy; A.S. Kiran Kumar
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Paper Abstract

We have proposed a method to determine the focal length of microlens array (MLA) based on the measurement of transverse displacement of image spot in the focal plane for a change of angle of incidence of plane wavefront. An existing interferometer test setup, meant for the surface figure measurement of MLA substrate, along with a charge-coupled device (CCD) is used for this purpose. The interferometer generates as well as measures the angle of incidence of plane wavefront at the MLA, and the transverse displacement of the image spot is determined from images recorded with the CCD. We have also discussed the theory of estimation of the focal length of MLA with spherical wavefront. Error analysis is carried out for both methods and is compared. The proposed plane wavefront method is experimentally demonstrated with an off-the-shelf MLA, and the measured focal length is within 1% of catalogue value.

Paper Details

Date Published: 4 December 2013
PDF: 8 pages
Opt. Eng. 52(12) 124103 doi: 10.1117/1.OE.52.12.124103
Published in: Optical Engineering Volume 52, Issue 12
Show Author Affiliations
M. Senthil Kumar, Space Applications Ctr. (India)
Chittur S. Narayanamurthy, Indian Institute of Space Science and Technology (India)
A.S. Kiran Kumar, Space Applications Ctr. (India)


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