Silicon Nitride MOMS Oscillator for Room Temperature Quantum Optomechanics

TL;DR

This paper presents a high-Q silicon nitride nano-oscillator operating at room temperature, suitable for quantum optomechanics and sensing, with innovative design and fabrication techniques enabling quantum ground-state cooling.

Contribution

The work introduces a high-stress SiN membrane oscillator with integrated seismic filtering, achieving a Q-frequency product suitable for quantum ground-state cooling at room temperature.

Findings

Mechanical quality factor of ~10^7 achieved

Q-frequency product exceeds 6.2 x 10^{12} Hz

Fabrication process allows additional layers for sensing applications

Abstract

Optomechanical SiN nano-oscillators in high-finesse Fabry-Perot cavities can be used to investigate the interaction between mechanical and optical degree of freedom for ultra-sensitive metrology and fundamental quantum mechanical studies. In this work we present a nano-oscillator made of a high-stress round-shaped SiN membrane with an integrated on-chip 3D seismic filter properly designed to reduce mechanical losses. This oscillator works in the 200 kHz - 5 MHz range and features a mechanical quality factor of $Q\simeq10^7$ and a Q-frequency product in excess of $6.2 \times 10^{12}$ Hz at room temperature, fulfilling the minimum requirement for quantum ground-state cooling of the oscillator in an optomechanical cavity. The device is obtained by MEMS DRIE bulk micromachining with a two-side silicon processing on a Silicon-On-Insulator (SOI) wafer. The microfabrication process is quite flexible and additional layers could be deposited over the SiN membrane before the DRIE steps, if required for a sensing application. Therefore, such oscillator is a promising candidate for quantum sensing applications in the context of the emerging field of Quantum Technologies.