Effects of uncertain phase-matching wave vectors of rotating fan-out type poled LiNbO3 on THz generation

Abstract

We investigated terahertz pulses from a rotating fan-out type poled lithium niobate (LiNbO3) pumped by femtosecond laser pulses. In particular, the rotating fan-out type poled sample produces an uncertain phase-matching wave vector perpendicular to input laser pulses. Such a wave vector allowed us to observe terahertz pulses normally unobservable from bulk or periodically poled LiNbO3 at large rotation angles because of the terahertz wave critical angle of LiNbO3. Further, we explained center frequency dependence on rotation angles by difference frequency generation process with the uncertain wave vector. We also discussed bandwidth dependence and terahertz pulse power regarding rotation angles. (C) 2010 Optical Society of America