Efficient generation of coherent THz phonons with a strong change in frequency excited by femtosecond laser plasma formed in a bulk of quartz
Faculty of Physics and International Laser Centre, Moscow State
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Received in final form: 25 June 2012
Published online: 28 September 2012
We observed a strong change in the frequency of coherent THz phonons from 1.4 to 4.6 THz under tight focusing (NA ~ 0.4) of intense femtosecond laser radiation (~ 1013 W/cm2) ignited the plasma within a bulk of quartz. Strong frequency shifts are caused by local heating of a microvolume (4 × 4 × 60 μm3) up to the temperature close to the α-β phase transition (846 K) of quartz. The effective target heating and coherent phonon excitation are provided via a laser-induced plasma.
Key words: Optical Phenomena and Photonics
© EDP Sciences, Società Italiana di Fisica and Springer-Verlag 2012