Terahertz emission from coherent phonons in lithium ternary chalcopyrite crystals illuminated by 1560 nm femtosecond laser pulses
Institute of Laser Engineering, Osaka University - 2-6 Yamadaoka, Suita, Osaka 565-0871, Japan
2 Graduate School of Engineering, Osaka University - 2-1 Yamadaoka, Suita, Osaka 565-0871, Japan
Accepted: 13 July 2010
We have investigated terahertz (THz) emission from lithium ternary chalcopyrite crystals LiInSe2, LiGaSe2, LiInS2, and LiGaS2 that were illuminated by 1560 nm femtosecond pump laser pulses. Monocyclic THz emission caused by nonlinear optical effects was initially observed in all the illuminated crystals. Narrow-band THz emission from the coherent phonons were observed in LiInSe2 (2.87 THz) and LiGaSe2 (2.60 and 3.45 THz). These phonon modes were most likely caused by impulsive stimulated Raman scattering.
PACS: 07.57.Pt – Submillimeter wave, microwave and radiowave spectrometers; magnetic resonance spectrometers, auxiliary equipment, and techniques / 42.70.Mp – Nonlinear optical crystals / 63.20.K- – Phonon interactions
© EPLA, 2010