{"id":4776,"date":"2018-03-04T11:24:09","date_gmt":"2018-03-04T16:24:09","guid":{"rendered":"http:\/\/labrigger.com\/blog\/?p=4776"},"modified":"2018-03-04T11:26:53","modified_gmt":"2018-03-04T16:26:53","slug":"remote-focusing-with-deformable-mirrors","status":"publish","type":"post","link":"http:\/\/labrigger.com\/blog\/2018\/03\/04\/remote-focusing-with-deformable-mirrors\/","title":{"rendered":"Remote focusing with deformable mirrors"},"content":{"rendered":"

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There are lots of ways to quickly change the z-focus plane, including tunable lenses<\/a>, piezo objective movers<\/a>, and a coupled objective<\/a>. What is the best<\/em><\/strong> way to change the Z-focus plane? It’s probably using a deformable mirror. They can be updated at kHz rates (settling time around 0.02 – 0.10 ms<\/a>), they can actively compensate for all sorts of optical aberrations (spherical aberration occurs in various defocusing approaches, e.g., tunable lenses), light loss is minimal, and they provide a good range of z-travel. How much travel? For an answer to that, check out the Shain et al. paper from Jerome Mertz’ group<\/a> at Boston University. <\/p>\n

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Given that deformable mirrors on the market have stroke lengths up to 80 microns<\/a>, this implies travel of a millimeter or more. For example, for NA = 0.6, n = 1.33, S = 80, and Rp\/Rdm = 1, the travel is about 2.1 mm.<\/p>\n

Martin Booth (who co-authored the original coupled-objective method of remote focusing with Tony Wilson) published this nice related work<\/a> recently (which cites Jerome’s paper linked to above). \u017durauskas et al. note that:<\/p>\n

Furthermore, the DM [deformable mirror] used for fast remote focusing, can be simultaneously employed to cancel sample induced aberrations and further increase SNR to boost practical imaging rates.<\/p><\/blockquote>\n

\u017durauskas et al. included wavefront sensing in their setup (below). This is great, and the paper has a lot of useful information. That said, if you’re interested in trying this out, it’s not essential to do wavefront sensing. You can just put a DM in a conjugate plane in your scan engine and optimize using the image as feedback (e.g., adjust the first 10 or so Zernike coefficients<\/a> of the DM command, one-at-a-time, to increase mean brightness) to get a feel for how it could work in your system.
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There are lots of ways to quickly change the z-focus plane, including tunable lenses<\/a>, piezo objective movers<\/a>, and a coupled objective<\/a>. What is the best<\/em><\/strong> way to change the…<\/p>\n

Read More<\/a><\/div><\/p>\n","protected":false},"author":1,"featured_media":4780,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[6],"tags":[21,15],"class_list":["post-4776","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-hardware","tag-imaging","tag-optics"],"_links":{"self":[{"href":"http:\/\/labrigger.com\/blog\/wp-json\/wp\/v2\/posts\/4776","targetHints":{"allow":["GET"]}}],"collection":[{"href":"http:\/\/labrigger.com\/blog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"http:\/\/labrigger.com\/blog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"http:\/\/labrigger.com\/blog\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"http:\/\/labrigger.com\/blog\/wp-json\/wp\/v2\/comments?post=4776"}],"version-history":[{"count":13,"href":"http:\/\/labrigger.com\/blog\/wp-json\/wp\/v2\/posts\/4776\/revisions"}],"predecessor-version":[{"id":4792,"href":"http:\/\/labrigger.com\/blog\/wp-json\/wp\/v2\/posts\/4776\/revisions\/4792"}],"wp:featuredmedia":[{"embeddable":true,"href":"http:\/\/labrigger.com\/blog\/wp-json\/wp\/v2\/media\/4780"}],"wp:attachment":[{"href":"http:\/\/labrigger.com\/blog\/wp-json\/wp\/v2\/media?parent=4776"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"http:\/\/labrigger.com\/blog\/wp-json\/wp\/v2\/categories?post=4776"},{"taxonomy":"post_tag","embeddable":true,"href":"http:\/\/labrigger.com\/blog\/wp-json\/wp\/v2\/tags?post=4776"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}