Terahertz Pulses with Strong DC Precursors

Concurrent processes of optical rectification and multiphoton absorption of high-intense ultrashort laser pulses in electro-optic crystals can generate terahertz pulses with strong DC precursors. We explore this phenomenon by numerical modeling and propose ways to maximize the precursor fields. In particular, we demonstrate that chirped-pulse pumping can compensate for the pump depletion, whereas tilted-pulse-front pumping allows one to increase the precursor fields by orders of magnitude.