We present a new technique for the fine alignment sensing of optical interferometers. Unlike conventional wavefront sensing systems, which use multielement photodiodes, this approach works with a single-element photodiode, in combination with a spatial light modulator (SLM) and digitally enhanced heterodyne interferometry. As all signals pass through a single photodetection and analog path, the technique exhibits high common-mode rejection to low frequency errors present in conventional systems. By changing the modulation pattern on the SLM, the technique can also be extended to sensing higher-order wavefront errors. In this paper, we demonstrate the technique experimentally and compare performance with a conventional heterodyne wavefront sensing system. This may improve and simplify alignment systems in space-based interferometers such as the planned LISA gravitational wave detector and provide a way to optimize the power in laser cavities not possible with the traditional segmented diode approach.
© 2017 Optical Society of AmericaFull Article | PDF Article
OSA Recommended Articles
Gerald Hechenblaikner, Rüdiger Gerndt, Ulrich Johann, Peter Luetzow-Wentzky, Vinzenz Wand, Heather Audley, Karsten Danzmann, Antonio Garcia-Marin, Gerhard Heinzel, Miquel Nofrarias, and Frank Steier
Appl. Opt. 49(29) 5665-5677 (2010)
Shuai Wang, Ping Yang, Mingwu Ao, Lizhi Dong, and Bing Xu
Appl. Opt. 53(35) 8342-8349 (2014)
J. Opt. Soc. Am. A 27(9) 2078-2083 (2010)