Detailed study on optical properties of Li2B4O7 for down-conversion to millimeter waves

Optical properties of single axes Li2B4O7 (LB4) crystal are defined at room temperature in the spectral range 0.03˗0.5 THz. Dispersion of the refractive index components are approximated in the form of Sellmeier equations. Dispersion properties were used to determine phase-matching conditions for THz wave generation by collinear difference frequency generation processes. To the damage threshold under the pump by train of hundreds of 60 fs pulses of Ti:sapphire laser operating at 950 nm is found to be 250 TW/cm2, as well as the coherence length and efficiency of all possible types of three wave interactions are defined.