Open AccessUltrafast imaging of terahertz Cherenkov waves and transition-like radiation in LiNbO_3
Author(s) -
Zhenyou Wang,
Fuhai Su,
Frank A. Hegmann
Publication year - 2015
Publication title -
optics express
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.394
H-Index - 271
ISSN - 1094-4087
DOI - 10.1364/oe.23.008073
Subject(s) - optical rectification , cherenkov radiation , terahertz radiation , optics , femtosecond , laser , ultrashort pulse , materials science , lithium niobate , transition radiation , radiation , optoelectronics , physics , nonlinear optics , detector
We use ultrafast phase-contrast imaging to directly observethe cone-like terahertz (THz) Cherenkov wave generated by optical rectification of femtosecond laser pulses focused into bulk lithium niobate (LiNbO₃) single crystals. The transverse imaging geometry allows the Cherenkov angle, THz wave velocity, and optical pump pulse group velocity to be measured. Furthermore, transition-like THz radiation generated by the femtosecond laser pulse at the air-crystal boundary is observed. The effect of optical pump pulse polarization on the generation of THz Cherenkov waves and transition-like radiation in LiNbO₃ is also investigated.