Clamped and sideband-resolved silicon optomechanical crystals

Journal article, 2023

Optomechanical crystals (OMCs) are a promising and versatile platform for transduction between mechanical and optical fields. However, the release from the substrate used in conventional suspended OMCs also complicates manufacturing and severely reduces thermal anchoring. This may be improved by attaching the OMCs directly to the substrate. Previous work towards such clamped, i.e., non-suspended, OMCs suffers from weak interaction rates and insufficient lifetimes. Here, we present a class of clamped OMCs realizing—for the first time, to our knowledge—optomechanical interactions in the resolved-sideband regime required for quantum transduction. Our approach leverages high-wavevector mechanical modes outside the continuum. We observe a record zero-point optomechanical coupling rate of g0/(2π) ≈ 0.50 MHz along with a sevenfold improvement in the single-photon cooperativity of clamped OMCs. Our devices operate at frequencies commonly used in superconducting qubits. This opens an avenue using clamped OMCs in both classical and quantum communications, sensing, and computation through scalable mechanical circuitry that couples strongly to light.