{"id":286,"date":"2018-06-19T06:41:58","date_gmt":"2018-06-19T06:41:58","guid":{"rendered":"http:\/\/www.shalomeo.com\/blog\/?p=286"},"modified":"2018-06-19T06:42:56","modified_gmt":"2018-06-19T06:42:56","slug":"relevant-aspects-for-the-choice-of-nonlinear-crystals","status":"publish","type":"post","link":"https:\/\/www.shalomeo.com\/blog\/relevant-aspects-for-the-choice-of-nonlinear-crystals\/286.html","title":{"rendered":"Relevant Aspects for the Choice of Nonlinear Crystals"},"content":{"rendered":"<p>Many different properties of a <a href=\"http:\/\/www.shalomeo.com\/category\/nlos-crystals-10.html\"><strong>nonlinear crystal<\/strong><\/a> can be important for an application e.g. in nonlinear frequency conversion:<\/p>\n<p>The chromatic dispersion and birefringence properties determine the possibilities for phase matching and the phase-matching bandwidth, angular acceptance (for critical phase matching), etc.<br \/>\nThe magnitude of the effective nonlinear coefficient deff, which depends on the nonlinear tensor components and on the phase-matching configuration, is important particularly if the achievable optical intensities are low.<br \/>\nNormally, the crystal material should have a high optical transparency for all wavelengths involved.<\/p>\n<p>Additional properties can be relevant for a comparison:<\/p>\n<p>the material&#8217;s potential to be periodically poled to achieve quasi-phase matching<br \/>\nlinear absorption, which can cause heating at high optical power levels, so that the phase matching is disturbed, and thermal lensing may occur<br \/>\nthe resistance against optical damage, gray tracking, photodarkening, green-induced infrared absorption, and the like<br \/>\nthe resistance against photorefractive effects (which are often called photorefractive damage, even though this is usually reversible)<br \/>\nthe availability of crystals with consistently good quality, large size and a reasonable price<br \/>\nthe ease of fabricating high-quality anti-reflection coatings on the crystals<br \/>\nthe chemical durability; e.g., some crystal materials are hygroscopic, others undergo chemical changes when heated in a vacuum chamber for application of a dielectric coating<br \/>\nThe choice of the most suitable crystal material for a given application is often far from trivial; it should involve the consideration of many aspects. For example, a high nonlinearity for frequency conversion of ultrashort pulses does not help if the interaction length is strongly limited by a large group velocity mismatch and the low damage threshold limits the applicable optical intensities. Also, it can be highly desirable to use a crystal material which can be critically phase-matched at room temperature, because noncritical phase matching often involves the operation of the crystal in a temperature-stabilized crystal oven.<\/p>\n<p><img decoding=\"async\" loading=\"lazy\" class=\"alignnone size-medium wp-image-287\" src=\"http:\/\/www.shalomeo.com\/blog\/wp-content\/uploads\/2018\/06\/lbo0619-300x212.jpg\" alt=\"\" width=\"300\" height=\"212\" \/><\/p>\n","protected":false},"excerpt":{"rendered":"<p>Many different properties of a nonlinear crystal c &hellip;<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":[],"categories":[1],"tags":[89],"_links":{"self":[{"href":"https:\/\/www.shalomeo.com\/blog\/wp-json\/wp\/v2\/posts\/286"}],"collection":[{"href":"https:\/\/www.shalomeo.com\/blog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.shalomeo.com\/blog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.shalomeo.com\/blog\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/www.shalomeo.com\/blog\/wp-json\/wp\/v2\/comments?post=286"}],"version-history":[{"count":0,"href":"https:\/\/www.shalomeo.com\/blog\/wp-json\/wp\/v2\/posts\/286\/revisions"}],"wp:attachment":[{"href":"https:\/\/www.shalomeo.com\/blog\/wp-json\/wp\/v2\/media?parent=286"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.shalomeo.com\/blog\/wp-json\/wp\/v2\/categories?post=286"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.shalomeo.com\/blog\/wp-json\/wp\/v2\/tags?post=286"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}