Terahertz generation by femtosecond laser pulses with tilted intensity front in room-temperature and cryogenically cooled LiNbO3 crystals was investigated. The role of the interaction length and pump pulse duration was studied for weak and strong laser pump. It was shown that the optical-to-terahertz conversion efficiency is saturated as a result of the Kerr self-phase modulation of the optical pump.
REFERENCES
To optimize THz generation (see Ref. 12), we set an incident angle on the grating and tuned the distance between the grating and the spherical mirror as well as the LN crystal position (along the z axis) to maximize THz energy.
For estimation, we assumed that 0.01% of the pump energy ∼1 mJ was absorbed near the region of maximum intensity in 2 × 2 × 1 mm3 volume of the LN.