{"id":66,"date":"2016-02-17T11:49:30","date_gmt":"2016-02-17T11:49:30","guid":{"rendered":"http:\/\/bifi.es\/~acastro\/?p=66"},"modified":"2016-02-17T18:40:32","modified_gmt":"2016-02-17T18:40:32","slug":"enhancing-and-contro-lling-single-atom-high-harmonic-generation-spectra-a-time-dependent-density-functional-scheme","status":"publish","type":"post","link":"https:\/\/personal.unizar.es\/acastro\/?p=66","title":{"rendered":"Enhancing and controlling single-atom high-harmonic generation spectra: a time-dependent density-functional scheme"},"content":{"rendered":"<p>A. Castro, A. Rubio, and E. K. U. Gross,\u00a0<a href=\"http:\/\/dx.doi.org\/10.1140\/epjb\/e2015-50889-7\" target=\"_blank\">Eur. Phys. J. B <strong>88<\/strong>, 191 (2015)<\/a>.<\/p>\n<p>High harmonic generation (HHG) provides a flexible framework for the development of coherent\u00a0light sources in the extreme-ultraviolet and soft X-ray regimes. However it suffers from low conversion\u00a0efficiencies as the control of the HHG spectral and temporal characteristics requires manipulating electron\u00a0trajectories on attosecond time scale. The phase matching mechanism has been employed to selectively\u00a0enhance specific quantum paths leading to HHG. A few important fundamental questions remain open,\u00a0among those how much of the enhancement can be achieved by the single-emitter and what is the role of<br \/>\ncorrelations (or the electronic structure) in the selectivity and control of HHG generation. Here we address\u00a0those questions by examining computationally the possibility of optimizing the HHG spectrum of isolated\u00a0hydrogen and helium atoms by shaping the slowly varying envelope of a 800 nm, 200-cycles long laser\u00a0pulse. The spectra are computed with a fully quantum mechanical description, by explicitly computing\u00a0the time-dependent dipole moment of the systems using a time-dependent density-functional approach\u00a0(or the single-electron Schr\u00f6odinger equation for the case of H), on top of a one-dimensional model. The\u00a0sought optimization corresponds to the selective enhancement of single harmonics, which we find to be\u00a0significant. This selectivity is entirely due to the single atom response, and not to any propagation or\u00a0phase-matching effect. Moreover, we see that the electronic correlation plays a role in the determining the\u00a0degree of optimization that can be obtained.<\/p>\n<p><a href=\"http:\/\/bifi.es\/~acastro\/wp-content\/uploads\/2016\/02\/fig2.jpg\" rel=\"attachment wp-att-86\"><img loading=\"lazy\" decoding=\"async\" class=\"aligncenter wp-image-86 size-medium\" src=\"http:\/\/bifi.es\/~acastro\/wp-content\/uploads\/2016\/02\/fig2-144x300.jpg\" alt=\"fig2\" width=\"144\" height=\"300\" srcset=\"https:\/\/personal.unizar.es\/acastro\/wp-content\/uploads\/2016\/02\/fig2-144x300.jpg 144w, https:\/\/personal.unizar.es\/acastro\/wp-content\/uploads\/2016\/02\/fig2-492x1024.jpg 492w, https:\/\/personal.unizar.es\/acastro\/wp-content\/uploads\/2016\/02\/fig2.jpg 527w\" sizes=\"(max-width: 144px) 100vw, 144px\" \/><\/a><\/p>\n","protected":false},"excerpt":{"rendered":"<p>A. Castro, A. Rubio, and E. K. U. Gross,\u00a0Eur. Phys. J. B 88, 191 (2015). High harmonic generation (HHG) provides a flexible framework for the development of coherent\u00a0light sources in the extreme-ultraviolet and soft X-ray regimes. However it suffers from low conversion\u00a0efficiencies as the control of the HHG spectral and temporal characteristics requires manipulating electron\u00a0trajectories [&hellip;]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"closed","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[1],"tags":[],"class_list":["post-66","post","type-post","status-publish","format-standard","hentry","category-uncategorized"],"_links":{"self":[{"href":"https:\/\/personal.unizar.es\/acastro\/index.php?rest_route=\/wp\/v2\/posts\/66"}],"collection":[{"href":"https:\/\/personal.unizar.es\/acastro\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/personal.unizar.es\/acastro\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/personal.unizar.es\/acastro\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/personal.unizar.es\/acastro\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=66"}],"version-history":[{"count":5,"href":"https:\/\/personal.unizar.es\/acastro\/index.php?rest_route=\/wp\/v2\/posts\/66\/revisions"}],"predecessor-version":[{"id":87,"href":"https:\/\/personal.unizar.es\/acastro\/index.php?rest_route=\/wp\/v2\/posts\/66\/revisions\/87"}],"wp:attachment":[{"href":"https:\/\/personal.unizar.es\/acastro\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=66"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/personal.unizar.es\/acastro\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=66"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/personal.unizar.es\/acastro\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=66"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}