Abstract
We demonstrate a 40 W peak power terahertz (THz) wave from an off-axis parametric oscillator by pumping a y-cut monolithic lithium niobate slab crystal with a pulsed laser at 1064 nm. This is a demonstration that, for the first time, a THz parametric oscillator resonates a THz wave, having the advantages of compact size, easy alignment, and high efficiency. The experimental results show that the efficiency of such a monolithic parametric oscillator is significantly larger than of a THz parametric generator using the same crystal dimensions.