研究概要 |
In FY2013 I made a good progress in my research on the novel high-order harmonics generation regime. Previously (in FY2012), I found that the harmonics are emitted from tiny sources. However, the imaging XUV system was astigmatic, which limited the spatial resolution. In FY2013 in a new experiment with the J-KAREN laser (JAEA), I increased the magnification and suppressed astigmatism, achieving ~5 micrometer spatial resolution with the CCD-based spectrograph and sub-micrometer resolution with a LiF crystal detector in the 60-100 eV photon energy range. This gave harmonics source images smaller than a micron. Physical optics propagation simulations indicate that the source size is about 0.2 micron. I have also measured double-point source structure, thus experimentally confirming a major prediction of our model of harmonics generation. I found that the 3-channel flat-field spectrograph built in FY2011-12 of this Kakenhi had a vacuum leak causing problems for turbo-molecular pumps. I repaired the spectrograph, reducing leak by two orders of magnitude. I have published in co-authorship 4 papers in refereed journals and submitted to New Journal of Physics a comprehensive paper about the novel harmonics generation regime. I made 2 Invited, 4 oral, and 1 poster presentations at 5 international and 2 domestic conferences, including an Invited talk at CLEO:2013 in San Jose. One more Invited presentation is scheduled (International Symposium "Topical Problems of Nonlinear Wave Physics-2014", 17-23 July, Russia).
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