Integrated optical-readout of a high-Q mechanical out-of-plane mode

摘要

The rapid development of high-QM macroscopic mechanical resonators has enabled great advances in optomechanics.Further improvements could allow for quantum-limited or quantum-enhanced applications at ambient temperature.Some of the remaining challenges include the integration of high-QM structures on a chip,while simultaneously achieving large coupling strengths through an optical read-out.Here,we present a versatile fabrication method,which allows us to build fully integrated optomechanical structures.We place a photonic crystal cavity directly above a mechanical resonator with high-QM fundamental out-of-plane mode,separated by a small gap.The highly confined optical field has a large overlap with the mechanical mode,enabling strong optomechanical interaction strengths.Furthermore,we implement a novel photonic crystal design,which allows for a very large cavity photon number,a highly important feature for optomechanical experiments and sensor applications.Our versatile approach is not limited to our particular design but allows for integrating an out-of-plane optical read-out into almost any device layout.Additionally,it can be scaled to large arrays and paves the way to realizing quantum experiments and applications with mechanical resonators based on high-QM out-of-plane modes alike.