Widely Tunable THz-Wave Generation by Nonlinear Optics

Hiromasa ITO  Kodo KAWASE  Jun-ichi SHIKATA  

IEICE TRANSACTIONS on Electronics   Vol.E81-C   No.2   pp.264-268
Publication Date: 1998/02/25
Online ISSN: 
Print ISSN: 0916-8516
Type of Manuscript: Special Section PAPER (Special Issue on Ultrashort Optical Pulse Technologies and their Applications)
Category: THz Wave Generation and Applications
nonlinear optics,  THz wave,  tunable,  parametric oscillation,  cryogenic cooling,  

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Widely tunable coherent terahertz (THz)-wave generation was successfully demonstrated based on the laser light scattering from the lowest A1-symmetry polariton mode by using a Q-switched Nd:YAG laser pumping. This method exhibits multiple advantages like wide tunability (frequency: 0. 9-2. 2 THz), coherency and compactness of its system. In this paper, the general performances of this THz-wave generator, as well as the recent development of the system and its application are reported. Measurements of tunability, coherency, power, polarization, radiation angle, and divergence are shown. The cryogenic cooling of the crystal was performed in addition, and a more than one hundred times higher THz-wave output was observed. A spectroscopic application of our wave source is demonstrated by measuring the water vapor absorption.