Tuning fork optomechanical NIR antenna with integrated optical transmission line

We present a novel optomechanical antenna design that directly converts near-infrared (λ=1.55 μm) light into mechanical motion using a tuning fork architecture with an integrated optical transmission line (OTL). The design consists of two parallel nanocantilever arms, made of gold-coated silicon nitride, forming a lateral tuning fork, with a plasmonic nanodipole antenna at the free end. Upon focused NIR laser illumination, our simulation results indicate that the nanodipole’s feed gap concentrates the optical field and induces an oscillating voltage across the gap. This produces a strong DC electrostatic attraction between the tuning fork arms, causing an in-plane deflection. The integrated coplanar optical transmission line significantly enhances the antenna’s performance by improving impedance matching, leading to nearly an order-of-magnitude higher gap voltage compared to designs without OTL. We verified the static mechanical response using COMSOL multiphysics simulations. An optimized design exhibits a lateral displacement up to 24.6 nm at 8 mW optical power, which corresponds to a responsivity of 3 nm/mW at 1.55 μm, outperforming previous NIR optomechanical transducers. • A tuning fork–based optomechanical antenna enabling direct NIR (1.55 µm) light-to-motion transduction is presented. • An integrated optical transmission line enhances impedance matching, yielding nearly one-order-of-magnitude higher gap voltage. • Electrostatic in-plane actuation eliminates photothermal crosstalk inherent to out-of-plane optomechanical designs. • Multiphysics simulations predict lateral displacements up to 24.6 nm at 8 mW optical power. • The optimized device achieves a responsivity of 3 nm/mW, outperforming previously reported NIR optomechanical transducers.