Second-Harmonic Generation in GaAs Photonic Crystal Cavities in (111)B and (001) Crystal Orientations

We demonstrate second-harmonic generation in photonic crystal cavities in (001)- and (111)B-oriented GaAs. The fundamental resonance is at 1800 nm, leading to generated second harmonic below the GaAs band gap. Below-band-gap operation minimizes absorption of the second-harmonic and two-photon absorption of the pump. Photonic crystal cavities were fabricated in both orientations at various in-plane rotations of the GaAs substrate. The rotation dependence and far-field patterns of the second harmonic match simulation. We observe similar maximum efficiencies of 1.2%/W in (001)- and (111)B-oriented GaAs.