Multiply resonant photonic crystal nanocavities for nonlinear frequency conversion

Abstract

We describe a photonic crystal nanocavity with multiple spatially overlapping resonances that can serve as a platform for nonlinear frequency conversion. We show nonlinear characterization of structures with two resonances nearly degenerate in frequency. We also demonstrate structures with resonances separated by up to 523 nm.

Multimode nanobeam cavities for nonlinear optics: high quality resonances separated by an octave

“…This is similar to overlaps achieved in TE/TM nano beams [11]. The TE 002 mode has an overlap of 0.063, similar to the overlap achieved in crossbeam cavities [47], but with a much larger frequency separation and maintaining similar Q factors. Further improvement on these designs could use inverse design [48] or genetic algorithms [49] to optimize these resonances at widely spaced frequencies.…”

“…1 can be simplified. The exact form of the simplification depends on the symmetry of the χ (2) tensor and the polarization of the constant field, but in the case of the (001) GaAs crystal orientation where the mode at ω 1 is TE polarized and the mode at ω 2 is TM polarized, this can be approximated [8,12,46] as…”

“…This discrepancy can in part be attributed to the difficulty in achieving the dispersion engineering necessary for meeting the phase-matching condition for photonic modes that are very far apart in frequency. For microcavities with strong mode localization, this requires solving the challenging problem of engineering high quality factor (Q) modes with large frequency separations that maintain good spatial overlap [8][9][10][11]. Realizing such low power, high efficiency devices could have applications in quantum information processing for on-chip frequency down-conversion of flying qubits emitted by solid state emitters such as InAs quantum dots (QDs) to telecommunications wavelengths [12], or up-conversion to the optimal frequency window for single photon detection [13].…”

“…Four wave mixing in coupled nanobeam cavities has been demonstrated [40], while the TE/TM nanobeam cavities proposed for broadband frequency conversion of single photons have been fabricated in silicon [11,41], but have yet to be implemented in high χ (2) materials. Crossed nanobeam PCCs [8,9] offer another method for increasing the frequency separation of the resonances, as the ability to individually select their wavelengths is significantly improved and the thickness of the wafer is less critical; however such cavities work well only when the frequency separation of the nanobeams is not too large.…”

Whispering Gallery Modes Formation in Small Nanocavities Based upon Crossed Nanobeam Structures

“…low-threshold nano-lasers, cavity quantum electrodynamics (QED) and non-linear Optics. For nonlinear optical interactions such as frequency conversion, it is anticipated to have multiple resonant nanostructures with arbitrary frequency separation plus good spatial field overlap [1][2][3][4].…”