Hexagonally poled lithium niobate: A two-dimensional nonlinear photonic crystal
We report on the fabrication of what we believe is the first example of a two-dimensional (2D) nonlinear photonic crystal [Berger, Phys. Rev. Lett. 81, 4136 (1998)], where the refractive index is constant but where the 2nd order nonlinear susceptibility is spatially periodic. Such crystals allow for efficient quasi-phase-matched 2nd harmonic generation using multiple reciprocal lattice vectors. External 2nd harmonic conversion efficiencies >60% were measured with picosecond pulses. The fabrication technique is extremely versatile and should allow for the fabrication of a broad range of 2D crystals including quasicrystals.
Broderick
NG
Optoelectronics Research Centre, University of Southampton, Southampton, SO17 1BJ, United Kingdom.
Ross
GW
Offerhaus
HL
Richardson
DJ
Hanna
DC