Tunable terahertz generation in periodically poled structures using femtosecond laser pulses

Terahertz generations were demonstrated in periodically poled lithium niobate and lithium tantalate crystals around 1-2 THz. Different forward and backward terahertz radiations are possible in periodically poled structures via difference frequency generation within the ultra-broad pump laser. The generated THz pulses could be controlled by the quasi-phase matching structures.