Terahertz wave generation in GaP waveguides by optical rectification with femtosecond bessel beam

Terahertz wave generation based on optical rectification in GaP waveguide emitters with a femtosecond zeroth-order Bessel beam was reported. The non-diffracting nature of the Bessel beam enabled an enhancement of the THz output power by factors of 3.46 and 3.34 from GaP waveguides of 6 and 10 mm, respectively, compared with a Gaussian beam having the same beam size and pump power as the central spot of the Bessel beam. The THz beams by both pumps featured a Gaussian distribution and the THz spectra by the Bessel beam showed evident red shifts.