Документ взят из кэша поисковой машины. Адрес оригинального документа : http://ofvp.phys.msu.ru/en/science_education/diploma/annot/2008/Potemkin_Mikhhev_en.pdf Дата изменения: Tue Dec 18 12:35:59 2007 Дата индексирования: Mon Oct 1 21:18:24 2012 Кодировка:

Investigation of the dynamics of plasma channels in fused silica formed by tightly focused Cr:Forsterite femtosecond laser radiation
diploma thesis by the six-year student Potemkin Fedor Viktorovitch

ABSTRACT
Dynamics of plasma channel formed by Cr:Forsterite femtosecond laser radiation tightly focused into the volume of fused silica was investigated in the degree research. The fundamental radiation with = 1.24 m and second harmonic radiation with = 0.62 m of Cr:Forsterite laser system was tightly focused by lens with numerical aperture NA=0.4 into the volume of fused silica. The plasma channel formation dynamics analysis was carried out using pump-probe method. The fundamental Cr:Forsterite laser radiation produced the electron-hole plasma in the volume of fused silica; the second harmonic Cr:Forsterite laser radiation delayed relative to fundamental laser radiation was absorbed by plasma electrons. Increasing probe pulse energy absorption up to 30% was observed at time delay up to
210 70 fs. The decrease of probe pulse energy was due to probe

pulse energy absorption by electrons of plasma produced by pump Cr:Forsterite laser radiation pulse. At picosecond time scale fused silica transmittance reached the value of 85%. Such behaviour can be explained by probe pulse scattering on destroying matter of fused silica (micromodificaion formation).

Scientific adviser, associate professor, candidate of physical and mathematical science

//Mikheev P.M.