Simultaneous generation and compression of broadband terahertz pulses in aperiodically poled crystals

Abstract

We introduce a technique to generate compressed broadband terahertz pulses based on cascaded difference-frequency generation. The approach employs a non-uniform sequence of pump pulses in aperiodically poled crystals. The pump-pulse format and poling of crystals conceived are such that the emergent terahertz pulse is already compressed. The method circumvents pump-pulse distortions that result from non-collinear approaches and the need for external compression. While capable of generating even single-cycle pulses, it is particularly efficient for the generation of pulses with few to tens-of-cycles duration. For instance, calculations accounting for cascading effects predict conversion efficiencies in the few percent range for cryogenically-cooled lithium niobate. The focused electric fields are 100 MV/m in free space.

On the effect of third-order dispersion on phase-matched terahertz generation via interfering chirped pulses

“…This discussion is inherently related to the generation of broadband DFG in aperiodically poled crystals [47,48], but that is beyond the scope of this article.…”