Terahertz pulses from titanium-doped lithium niobate strip optical waveguides using a 1.55-micrometer pump beam

We demonstrate that titanium-doped lithium niobate strip optical waveguides can act as terahertz emitters. Terahertz pulses were produced by pumping with a femtosecond laser at a wavelength of 1.55 μm via the prism-coupled Cherenkov-phase matching scheme. Near-single cycle time-domain pulses were generated and the terahertz time-domain peak signal from the 40-μm waveguide was found to be ~18% higher than that observed with bulk crystal. The THz power spectra revealed a broad bandwidth and high signal-to-noise ratio. These findings signify the feasibility of titanium-in-diffusion to produce strong terahertz radiation from titanium-doped lithium niobate waveguides.