{"id":259,"date":"2017-08-24T11:17:57","date_gmt":"2017-08-24T03:17:57","guid":{"rendered":"http:\/\/sheng.people.ust.hk\/?p=259"},"modified":"2017-08-25T10:48:02","modified_gmt":"2017-08-25T02:48:02","slug":"meso-structures-by-holographic-lithography","status":"publish","type":"post","link":"http:\/\/sheng.people.ust.hk\/?p=259","title":{"rendered":"Meso-structures by holographic lithography"},"content":{"rendered":"

Holographic lithography combines the techniques of holography and laser-induced polymerization in which a photo-resist is exposed to the interference pattern formed by multiple coherent laser beams.\u00a0 Regions with high intensity are polymerized, while under-exposed regions are washed away in a post-exposure process, leaving behind a 2D\/3D polymerized structure.\u00a0 This method is very flexible such that various structures, like SC, FCC and\u00a0BCC, can be fabricated by controlling the beam configurations, intensities, and polarizations.\u00a0 It can also be extended to aperiodic or quasi-periodic structures using five or more beam configurations.\u00a0 Furthermore, chiral structures are also possible by using circularly polarized beams.<\/p>\n

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Fig. 1:\u00a0Beam configuration of FCC structure<\/figcaption><\/figure>\n

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In the Physics Department of HKUST, we have several setups using an argon ion laser at 448nm and a HeCd laser at 325nm.\u00a0 FCC structures and 2D Penrose quasicrystals had been fabricated [1].\u00a0 We have also obtained interesting results for 3D quasicrystals, woodpiles, and spirals [2-4].\u00a0 Recently, we have used holographic gelatin plates instead of photoresists to record the interference patterns.\u00a0 The gelatin samples exhibit interesting photonic bandgaps.\u00a0\u00a0After doped with fluorescence dyes, the gelatin samples can also lase when excited.\u00a0\u00a0We have observed visible range lasing in 3D icosahedral quasicrystals for\u00a0the first time\u00a0[5].<\/p>\n

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Fig. 2:\u00a02D Penrose structures fabricated using a 5-beam configuration.<\/figcaption><\/figure>\n

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Fig. 3:\u00a0Spiral structures fabricated in photo-resist by holographic lithography<\/figcaption><\/figure>\n

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Fig. 4: Woodpile structures by holographic lithography<\/figcaption><\/figure>\n

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Fig. 5:\u00a0Lasing from icosahedral quasicrystals in holographic gelatin plate<\/figcaption><\/figure>\n

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Key Publications:<\/strong><\/p>\n

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  1. “Large area two-dimensional mesoscale quasicrystals”, X. Wang, C. Y. Ng, W. Y. Tam,\u00a0 C. T. Chan\u00a0and P. Sheng, Adv. Materials 15, 1526-1528 (2003).<\/em><\/li>\n
  2. \u201cChiral Microstructures (Spirals) Fabrication by Holographic Lithography\u201d, Yee Kwong Pang, Jeffrey\u00a0Chi Wai Lee, Hung Fai Lee, Wing Yim Tam*, C. T. Chan, and Ping Sheng, Optics Express 13,\u00a07615-7620 (2005).<\/em><\/li>\n
  3. \u201cRealization of Woodpile Structure Using Optical Interference Holography\u201d, Yee Kwong Pang,\u00a0Jeffrey Chi Wai Lee, Cheuk Ting Ho and Wing Yim\u00a0\u00a0Tam*, Optics Express 14, 9113-9119\u00a0(2006);http:\/\/arxiv.org\/ftp\/physics\/papers\/0607\/0607147.pdf<\/a>.<\/em><\/li>\n
  4. \u201cIcosahedral Quasicrystals for Visible Wavelength by Optical Interference Holography\u201d, Jun Xu, Rui Ma, Xia Wang and Wing Yim Tam, Optics Express 15, 4287-4295 (2007).<\/em><\/li>\n
  5. \u201cVisible Light Lasing From Dye-doped Icosahedral Quasicrystals in Dichromate Gelatin Emulsions\u201d, Mang Hin Kok, Weixin Lu, Wing Yim Tam*, and George K. L. Wong, Optics Express 17, 7275-7284\u00a0(2009).<\/em><\/li>\n<\/ol>\n","protected":false},"excerpt":{"rendered":"

    Holographic lithography combines the techniques of holography and laser-induced polymerization in which a photo-resist is exposed to the interference pattern formed by multiple coherent laser beams.\u00a0 Regions with high intensity are polymerized, while under-exposed regions are washed away in a post-exposure process, leaving behind a 2D\/3D polymerized structure.\u00a0 This method is very flexible such that … Continue reading Meso-structures by holographic lithography<\/span><\/a><\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":[],"categories":[5],"tags":[],"_links":{"self":[{"href":"http:\/\/sheng.people.ust.hk\/index.php?rest_route=\/wp\/v2\/posts\/259"}],"collection":[{"href":"http:\/\/sheng.people.ust.hk\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"http:\/\/sheng.people.ust.hk\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"http:\/\/sheng.people.ust.hk\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"http:\/\/sheng.people.ust.hk\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=259"}],"version-history":[{"count":4,"href":"http:\/\/sheng.people.ust.hk\/index.php?rest_route=\/wp\/v2\/posts\/259\/revisions"}],"predecessor-version":[{"id":274,"href":"http:\/\/sheng.people.ust.hk\/index.php?rest_route=\/wp\/v2\/posts\/259\/revisions\/274"}],"wp:attachment":[{"href":"http:\/\/sheng.people.ust.hk\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=259"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"http:\/\/sheng.people.ust.hk\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=259"},{"taxonomy":"post_tag","embeddable":true,"href":"http:\/\/sheng.people.ust.hk\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=259"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}