Probing nonequilibrium electron distributions in gold by use of second-harmonic generation.
نویسندگان
چکیده
Second-harmonic radiation is generated at a gold surface by use of a laser pulse that is varied in duration from 14 to 29 fs and in intensity from 10(9) to 10(11)W/cm(2) . At laser intensities below 10(10)W/cm(2) , the second-harmonic signal has the expected quadratic dependence on pump-laser intensity; however, at higher intensities, the dependence is supraquadratic. This difference arises because the leading edge of the laser pulse interacts significantly with the gold electrons to create a nonequilibrium, photoexcited distribution. The second-harmonic generation process occurs before electron-electron or electron-phonon collisions can equilibrate the distribution and therefore serves as a probe of the nonequilibrium distribution.
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ورودعنوان ژورنال:
- Optics letters
دوره 24 14 شماره
صفحات -
تاریخ انتشار 1999