Photonic crystal nanocavities fabricated from chalcogenide glass fully embedded in an index-matched cladding with a high Q-factor (>750,000)

Abstract

We have designed and fabricated a 2-D photonic crystal hetero-structure cavity in the chalcogenide glass Ge(11.5)As(24)Se(64.5) that is fully embedded in a cladding with refractive index of 1.44. The low index contrast of this structure (≈1.21) means that high-Q resonances cannot be obtained using standard hetero-structure cavity designs based on W1 waveguides. We show that reducing the waveguide width can substantially improve light confinement, leading to high-Q resonances in a hetero-structure cavity. Numerical simulations indicate intrinsic Q(v) > 10(7) are possible with this approach. Experimentally, an optical cavity with a high intrinsic Q(v)>7.6 x 10(5) was achieved in a structure with a theoretical Q(v) = 1.7 x 10(6).