We experimentally investigate the limits to 800 nm-to-terahertz (THz) energy
conversion in lithium niobate at room temperature driven by amplified
Ti:Sapphire laser pulses with tilted-pulse-front. The influence of the pump
central wavelength, pulse duration, and fluence on THz generation is studied.
We achieved a high peak efficiency of 0.12% using transform limited 150 fs
pulses and observed saturation of the optical to THz conversion efficiency at a
fluence of 15 mJ/cm2. We experimentally identify two main limitations for the
scaling of optical-to-THz conversion efficiencies: (i) the large spectral
broadening of the optical pump spectrum in combination with large angular
dispersion of the tilted-pulse-front and (ii) free-carrier absorption of THz
radiation due to multi-photon absorption of the 800 nm radiation.Comment: 4 pages, 6 figure