{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2025,10,12]],"date-time":"2025-10-12T04:38:29Z","timestamp":1760243909113,"version":"build-2065373602"},"reference-count":12,"publisher":"MDPI AG","issue":"11","license":[{"start":{"date-parts":[[2011,10,31]],"date-time":"2011-10-31T00:00:00Z","timestamp":1320019200000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/3.0\/"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Sensors"],"abstract":"<jats:p>In order to determine light aberrations, Shack-Hartmann optical wavefront sensors make use of microlens arrays (MLA) to divide the incident light into small parts and focus them onto image planes. In this paper, we present the design and fabrication of long focal length MLA with various shapes and arrangements based on a double layer structure for optical wavefront sensing applications. A longer focal length MLA could provide high sensitivity in determining the average slope across each microlens under a given wavefront, and spatial resolution of a wavefront sensor is increased by numbers of microlenses across a detector. In order to extend focal length, we used polydimethysiloxane (PDMS) above MLA on a glass substrate. Because of small refractive index difference between PDMS and MLA interface (UV-resin), the incident light is less refracted and focused in further distance. Other specific focal lengths could also be realized by modifying the refractive index difference without changing the MLA size. Thus, the wavefront sensor could be improved with better sensitivity and higher spatial resolution.<\/jats:p>","DOI":"10.3390\/s111110293","type":"journal-article","created":{"date-parts":[[2011,10,31]],"date-time":"2011-10-31T11:59:28Z","timestamp":1320062368000},"page":"10293-10307","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":26,"title":["An Optical Wavefront Sensor Based on a Double Layer Microlens Array"],"prefix":"10.3390","volume":"11","author":[{"given":"Vinna","family":"Lin","sequence":"first","affiliation":[{"name":"Graduate Institute of Photonics and Optoelectronics, National Taiwan University, No. 1, Roosevelt Road, Section 4, Taipei, Taiwan"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Hsiang-Chun","family":"Wei","sequence":"additional","affiliation":[{"name":"Graduate Institute of Photonics and Optoelectronics, National Taiwan University, No. 1, Roosevelt Road, Section 4, Taipei, Taiwan"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Hsin-Ta","family":"Hsieh","sequence":"additional","affiliation":[{"name":"Graduate Institute of Photonics and Optoelectronics, National Taiwan University, No. 1, Roosevelt Road, Section 4, Taipei, Taiwan"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Guo-Dung John","family":"Su","sequence":"additional","affiliation":[{"name":"Graduate Institute of Photonics and Optoelectronics, National Taiwan University, No. 1, Roosevelt Road, Section 4, Taipei, Taiwan"}],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"1968","published-online":{"date-parts":[[2011,10,31]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"573","DOI":"10.3928\/1081-597X-20010901-13","article-title":"History and principles of Shack-Hartmann wavefront sensing","volume":"17","author":"Platt","year":"2001","journal-title":"J. Refract. Surg"},{"key":"ref_2","doi-asserted-by":"crossref","first-page":"1949","DOI":"10.1364\/JOSAA.11.001949","article-title":"Objective measurement of wave aberrations of the human eye with the use of a Hartmann-Shack wave-front sensor","volume":"11","author":"Liang","year":"1994","journal-title":"J. Opt. Soc. Am. A"},{"key":"ref_3","doi-asserted-by":"crossref","first-page":"759","DOI":"10.1088\/0957-0233\/1\/8\/016","article-title":"The manufacture of microlenses by melting photoresist","volume":"1","author":"Daly","year":"1990","journal-title":"Meas. Sci. Tech"},{"key":"ref_4","doi-asserted-by":"crossref","unstructured":"Sinzinger, S., and Jahns, J. (2003). Microoptics, Wiley-VCH.","DOI":"10.1002\/3527603409"},{"key":"ref_5","unstructured":"Hecht, E. (2001). Optics, Addison-Wesley. [4th ed]."},{"key":"ref_6","doi-asserted-by":"crossref","first-page":"491","DOI":"10.1021\/ar010110q","article-title":"Poly(dimethylsiloxane) as a material for fabricating microfluidic devices","volume":"35","author":"McDonald","year":"2002","journal-title":"Acc. Chem. Res"},{"key":"ref_7","unstructured":"Fischer, R.E., Tadic-Galeb, B., and Yoder, P.R. (2008). Optical System Design, McGraw-Hill."},{"key":"ref_8","doi-asserted-by":"crossref","first-page":"188","DOI":"10.1364\/AO.35.000188","article-title":"Shack Hartmann wave-front measurement with a large F-number plastic microlens array","volume":"35","author":"Yoon","year":"1996","journal-title":"Appl. Opt"},{"key":"ref_9","doi-asserted-by":"crossref","unstructured":"Malacara, D. (2007). Optical Shop Testing, Wiley-Blackwell.","DOI":"10.1002\/9780470135976"},{"key":"ref_10","doi-asserted-by":"crossref","first-page":"480","DOI":"10.1117\/12.453645","article-title":"Measurement of the dynamic deformation of a high frequency scanning mirror using a Shack-Hartmann wavefront sensor","volume":"4451","author":"Brown","year":"2001","journal-title":"Proc. SPIE"},{"key":"ref_11","doi-asserted-by":"crossref","unstructured":"Greivenkamp, J.E., Smith, D.G., Gappinger, R.O., and Williby, G.A. (2001). Optical testing using Shack-Hartmann wavefront. Proc. SPIE, 4416.","DOI":"10.1117\/12.427063"},{"key":"ref_12","doi-asserted-by":"crossref","first-page":"063601","DOI":"10.1117\/1.2940143","article-title":"Graphical approach to Shack-Hartmann lenselet array design","volume":"47","author":"Greivenkamp","year":"2008","journal-title":"Opt. Eng"}],"container-title":["Sensors"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.mdpi.com\/1424-8220\/11\/11\/10293\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2025,10,11]],"date-time":"2025-10-11T21:57:52Z","timestamp":1760219872000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.mdpi.com\/1424-8220\/11\/11\/10293"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2011,10,31]]},"references-count":12,"journal-issue":{"issue":"11","published-online":{"date-parts":[[2011,11]]}},"alternative-id":["s111110293"],"URL":"https:\/\/doi.org\/10.3390\/s111110293","relation":{},"ISSN":["1424-8220"],"issn-type":[{"type":"electronic","value":"1424-8220"}],"subject":[],"published":{"date-parts":[[2011,10,31]]}}}