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Method for auto-alignment of digital optical phase conjugation systems based on digital propagation

Jang, Mooseok and Ruan, Haowen and Zhou, Haojiang and Judkewitz, Benjamin and Yang, Changhuei (2014) Method for auto-alignment of digital optical phase conjugation systems based on digital propagation. Optics Express, 22 (12). pp. 14054-14071. ISSN 1094-4087. PMCID PMC4083057.

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Optical phase conjugation (OPC) has enabled many optical applications such as aberration correction and image transmission through fiber. In recent years, implementation of digital optical phase conjugation (DOPC) has opened up the possibility of its use in biomedical optics (e.g. deep-tissue optical focusing) due to its ability to provide greater-than-unity OPC reflectivity (the power ratio of the phase conjugated beam and input beam to the OPC system) and its flexibility to accommodate additional wavefront manipulations. However, the requirement for precise (pixel-to-pixel matching) alignment of the wavefront sensor and the spatial light modulator (SLM) limits the practical usability of DOPC systems. Here, we report a method for auto-alignment of a DOPC system by which the misalignment between the sensor and the SLM is auto-corrected through digital light propagation. With this method, we were able to accomplish OPC playback with a DOPC system with gross sensor-SLM misalignment by an axial displacement of up to~1.5 cm, rotation and tip/tilt of ~5∘, and in-plane displacement of ~5 mm (dependent on the physical size of the sensor and the SLM). Our auto-alignment method robustly achieved a DOPC playback peak-to-background ratio (PBR) corresponding to more than ~30 % of the theoretical maximum. As an additional advantage, the auto-alignment procedure can be easily performed at will and, as such, allows us to correct for small mechanical drifts within the DOPC systems, thus overcoming a previously major DOPC system vulnerability. We believe that this reported method for implementing robust DOPC systems will broaden the practical utility of DOPC systems.

Item Type:Article
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URLURL TypeDescription CentralArticle
Yang, Changhuei0000-0001-8791-0354
Additional Information:© 2014 Optical Society of America. Received 20 Feb 2014; revised 5 May 2014; accepted 26 May 2014; published 2 Jun 2014. We thank Mr. Roarke Horstmeyer for helpful discussions. This work was supported by NIH 1DP2OD007307-01. Benjamin Judkewitz is a recipient of a Sir Henry Wellcome Fellowship from the Wellcome Trust.
Funding AgencyGrant Number
Issue or Number:12
Classification Code:OCIS codes: (070.5040); (070.7345); (090.1995) ; (090.2880); (110.7050); (220.1080) .
PubMed Central ID:PMC4083057
Record Number:CaltechAUTHORS:20140801-072531278
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Official Citation:Mooseok Jang, Haowen Ruan, Haojiang Zhou, Benjamin Judkewitz, and Changhuei Yang, "Method for auto-alignment of digital optical phase conjugation systems based on digital propagation," Opt. Express 22, 14054-14071 (2014)
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:47759
Deposited By: Ruth Sustaita
Deposited On:01 Aug 2014 16:15
Last Modified:09 Mar 2020 13:19

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