Eur. Phys. J. D (2012) 66: 248
https://doi.org/10.1140/epjd/e2012-30048-x

Regular Article

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 University, 119991 Moscow, Russia

^a e-mail: potemkin@automationlabs.ru

Received: 19 January 2012
Received in final form: 25 June 2012
Published online: 28 September 2012

Abstract

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.