{"id":455,"date":"2018-06-27T17:19:15","date_gmt":"2018-06-27T17:19:15","guid":{"rendered":"https:\/\/live-optics-wp.pantheonsite.io\/kkieu\/?page_id=455"},"modified":"2018-10-03T15:47:13","modified_gmt":"2018-10-03T15:47:13","slug":"dual-comb-spectroscopy","status":"publish","type":"page","link":"https:\/\/wp.optics.arizona.edu\/kkieu\/dual-comb-spectroscopy\/","title":{"rendered":"Dual Comb Spectroscopy"},"content":{"rendered":"<h3>Introduction<\/h3>\n<p>Dual comb spectroscopy (DCS) can achieve high spectral resolution and short acquisition time (compared to Fourier-transform spectroscopy) simultaneously since no moving parts are required. Traditional DCS uses phase locking to connect two femtosecond lasers, which requires complex electronics. Our designs address these issues by using a single laser cavity to generate both the probe and the local oscillator. We have made several variations since our original publication, broadening the useful spectral range, and shifting the wavelength in order to cover key H<sub>2<\/sub>0 and CO<sub>2<\/sub> absorption lines.<\/p>\n<p><strong>Students:\u00a0<\/strong>Yi-Shin Ou, Joshua Olsen<\/p>\n<h3>Recent Projects:<\/h3>\n<p><a href=\"https:\/\/ieeexplore.ieee.org\/abstract\/document\/8456546\">We demonstrated a Thulium fiber based DCS system.<\/a> This shifted our wavelength into the 2 micron range, and demonstrated single-shot DCS of H<sub>2<\/sub>0 absorption lines.<\/p>\n<div id=\"attachment_550\" style=\"width: 870px\" class=\"wp-caption alignnone\"><img loading=\"lazy\" decoding=\"async\" aria-describedby=\"caption-attachment-550\" class=\"wp-image-550 size-large\" src=\"https:\/\/wp.optics.arizona.edu\/kkieu\/wp-content\/uploads\/sites\/29\/2018\/06\/Josh-1024x242.jpg\" alt=\"\" width=\"860\" height=\"203\" srcset=\"https:\/\/wp.optics.arizona.edu\/kkieu\/wp-content\/uploads\/sites\/29\/2018\/06\/Josh-1024x242.jpg 1024w, https:\/\/wp.optics.arizona.edu\/kkieu\/wp-content\/uploads\/sites\/29\/2018\/06\/Josh-300x71.jpg 300w, https:\/\/wp.optics.arizona.edu\/kkieu\/wp-content\/uploads\/sites\/29\/2018\/06\/Josh-768x181.jpg 768w, https:\/\/wp.optics.arizona.edu\/kkieu\/wp-content\/uploads\/sites\/29\/2018\/06\/Josh.jpg 1156w\" sizes=\"auto, (max-width: 860px) 100vw, 860px\" \/><p id=\"caption-attachment-550\" class=\"wp-caption-text\">(a) Single-shot time-domain interferogram captured over 1 ms. Inset: Center-burst of the interferogram. (b) Recovered spectral magnitude from the single-shot time-domain interferogram (linear scale). (c) Water vapor absorption lines from the DCS measurement compared to HITRAN data<\/p><\/div>\n<p><a href=\"https:\/\/www.osapublishing.org\/abstract.cfm?uri=CLEO_SI-2017-SM2L.3\">We demonstrated an octave-spanning laser source for dual-comb spectroscopy<\/a>.\u00a0Two optical frequency combs (OFCs) were generated from a single laser cavity and frequency broadened to cover over an octave for broadband single shot DCS.<\/p>\n<div id=\"attachment_459\" style=\"width: 870px\" class=\"wp-caption aligncenter\"><img loading=\"lazy\" decoding=\"async\" aria-describedby=\"caption-attachment-459\" class=\"wp-image-459 size-large\" src=\"https:\/\/wp.optics.arizona.edu\/kkieu\/wp-content\/uploads\/sites\/29\/2018\/06\/DualComb-1024x303.jpg\" alt=\"\" width=\"860\" height=\"254\" srcset=\"https:\/\/wp.optics.arizona.edu\/kkieu\/wp-content\/uploads\/sites\/29\/2018\/06\/DualComb-1024x303.jpg 1024w, https:\/\/wp.optics.arizona.edu\/kkieu\/wp-content\/uploads\/sites\/29\/2018\/06\/DualComb-300x89.jpg 300w, https:\/\/wp.optics.arizona.edu\/kkieu\/wp-content\/uploads\/sites\/29\/2018\/06\/DualComb-768x227.jpg 768w, https:\/\/wp.optics.arizona.edu\/kkieu\/wp-content\/uploads\/sites\/29\/2018\/06\/DualComb.jpg 1211w\" sizes=\"auto, (max-width: 860px) 100vw, 860px\" \/><p id=\"caption-attachment-459\" class=\"wp-caption-text\">A schematic diagram of the laser system<\/p><\/div>\n<p><a href=\"https:\/\/aip.scitation.org\/doi\/abs\/10.1063\/1.4953400\">We presented a simple and robust dual-comb system that uses a free-running bidirectionally mode-locked\u00a0fiber laser\u00a0operating at telecommunication wavelength<\/a>. Two\u00a0femtosecond frequency combs (with a small difference in repetition rates) were generated from a single\u00a0laser cavity\u00a0to ensure mutual\u00a0coherent\u00a0properties and common noise cancellation. As a result, we achieved real-time absorption\u00a0spectroscopy measurements\u00a0without the need for complex servo locking with accurate frequency referencing, and relatively high signal-to-noise ratio. We used this laser to match to the NIST data for HCN gas, and found a close match in our results.<\/p>\n<div id=\"attachment_460\" style=\"width: 709px\" class=\"wp-caption alignnone\"><img loading=\"lazy\" decoding=\"async\" aria-describedby=\"caption-attachment-460\" class=\"wp-image-460 size-full\" src=\"https:\/\/wp.optics.arizona.edu\/kkieu\/wp-content\/uploads\/sites\/29\/2018\/06\/soroush-e1530120621557.gif\" alt=\"\" width=\"699\" height=\"362\" \/><p id=\"caption-attachment-460\" class=\"wp-caption-text\">15 absorption lines of HCN gas are shown. The absorption lines central frequencies deviate from the NIST SRM2519 database with \u223c207 MHz standard deviation<\/p><\/div>\n","protected":false},"excerpt":{"rendered":"<p>Introduction Dual comb spectroscopy (DCS) can achieve high spectral resolution and short acquisition time (compared to Fourier-transform spectroscopy) simultaneously since no moving parts are required. Traditional DCS uses phase locking to connect two femtosecond lasers, which requires complex electronics. Our designs address these issues by using a single laser cavity to generate both the probe and the local oscillator. We<\/p>\n","protected":false},"author":33,"featured_media":0,"parent":0,"menu_order":0,"comment_status":"closed","ping_status":"closed","template":"","meta":{"footnotes":""},"class_list":["post-455","page","type-page","status-publish","hentry"],"_links":{"self":[{"href":"https:\/\/wp.optics.arizona.edu\/kkieu\/wp-json\/wp\/v2\/pages\/455","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/wp.optics.arizona.edu\/kkieu\/wp-json\/wp\/v2\/pages"}],"about":[{"href":"https:\/\/wp.optics.arizona.edu\/kkieu\/wp-json\/wp\/v2\/types\/page"}],"author":[{"embeddable":true,"href":"https:\/\/wp.optics.arizona.edu\/kkieu\/wp-json\/wp\/v2\/users\/33"}],"replies":[{"embeddable":true,"href":"https:\/\/wp.optics.arizona.edu\/kkieu\/wp-json\/wp\/v2\/comments?post=455"}],"version-history":[{"count":12,"href":"https:\/\/wp.optics.arizona.edu\/kkieu\/wp-json\/wp\/v2\/pages\/455\/revisions"}],"predecessor-version":[{"id":458,"href":"https:\/\/wp.optics.arizona.edu\/kkieu\/wp-json\/wp\/v2\/pages\/455\/revisions\/458"}],"wp:attachment":[{"href":"https:\/\/wp.optics.arizona.edu\/kkieu\/wp-json\/wp\/v2\/media?parent=455"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}