title: Zonal wavefront sensor with reduced number of rows in the detector array.
abstract: In this paper, we describe a zonal wavefront sensor in which the photodetector array can have a smaller number of rows. The test wavefront is incident on a two-dimensional array of diffraction gratings followed by a single focusing lens. The periodicity and the orientation of the grating rulings of each grating can be chosen such that the +1 order beam from the gratings forms an array of focal spots in the detector plane. We show that by using a square array of zones, it is possible to generate an array of +1 order focal spots having a smaller number of rows, thus reducing the height of the required detector array. The phase profile of the test wavefront can be estimated by measuring the displacements of the +1 order focal spots for the test wavefront relative to the +1 order focal spots for a plane reference wavefront. The narrower width of the photodetector array can offer several advantages, such as a faster frame rate of the wavefront sensor, a reduced amount of cross talk between the nearby detector zones, and a decrease in the maximum thermal noise. We also present experimental results of a proof-of-concept experimental arrangement using the proposed wavefront sensing scheme.
authors: Department of Physics, Indian Institute of Technology Guwahati, Guwahati 781039, Assam, India. brboruah@iitg.ernet.in
authors: Bosanta R
authors: BR
authors: Boruah
authors: Abhijit
authors: A
authors: Das
mesh_terms: D000465:Algorithms; D004867:Equipment Design; D007091:Image Processing, Computer-Assisted; D021621:Imaging, Three-Dimensional; D007909:Lenses; D008027:Light; D050866:Liquid Crystals; D008853:Microscopy / Q000379:methods; D015233:Models, Statistical; D055095:Optics and Photonics; D010825:Physics / Q000379:methods