A Multi-Band Photonic Source by Means of Phase-Matched Nonlinear Generation Processes

A technique for multi-band generation is investigated to simultaneously achieve phase-matching in multiple second-order nonlinear processes. By coupling a near-infrared excitation pulse into a LiNbO
₃
planar waveguiding platform, modal phase-matched second harmonic radiation is generated at wavelengths of 403 ± 0.6 nm and Cherenkov-emitted terahertz radiation is generated at frequencies up to ~3.5 THz. For the second harmonic generation process and the terahertz radiation generation process, the conversion efficiencies are measured as 1.5 × 10
^-2
%/(GW-cm
^-2
) and 1.9 × 10
^-4
%/(GW-cm
^-2
), respectively. The investigated multi-band generation technique permits a single structure to produce radiation within multiple spectral bands, such that this technique could be used to increase the density of photonic sources on a photonic integrated chip.