Overview
The study investigates the use of sail membranes to develop optomechanical accelerometers, focusing on improving the performance characteristics of strained membrane resonators. The research details a class of sail-like trampoline resonators discovered through Bayesian optimization, designed to decrease operational frequency while preserving the quality factor-mass (Q-mass) product.
Research Context
Strained membrane resonators represent a platform for optomechanical accelerometry. A key challenge in this field involves achieving a combination of low frequency and a high Q-mass product, which typically necessitates specific engineering approaches for dissipation dilution.
Approach
The researchers applied Bayesian optimization to silicon nitride (Si$_3$N$_4$) membranes. This optimization method led to the discovery of specific resonator geometries characterized as sail-like trampoline resonators. The investigation included the vertical integration of a 7 kHz sail-like device with a nanoribbon to create a monolithic cavity optomechanical accelerometer.
Findings
- Bayesian optimization applied to Si$_3$N$_4$ membranes identified a class of sail-like trampoline resonators.
- These sail-like resonators demonstrated a reduction in frequency by an order of magnitude compared to initial configurations.
- The Q-mass product of the sail-like resonators was preserved despite the frequency reduction.
- Centimeter-scale sail membranes were observed to operate at kilohertz (kHz) frequencies, exhibiting quality factors ($Q$) around $10^7$ and a Q-mass product of approximately 10 g.
- A vertically integrated 7 kHz sail device with a nanoribbon formed a monolithic cavity optomechanical accelerometer.
- This accelerometer exhibited a room temperature thermal noise of $40\;\text{n}g_0/\sqrt{\text{Hz}}$.
- The demonstrated performance is sufficient to resolve $\mu g_0/\sqrt{\text{Hz}}$ ambient vibration across a 4 kHz bandwidth.
- The displacement imprecision of the device was measured at $10^{-14}\;\text{m}/\sqrt{\text{Hz}}$.
Potential Applications
The researchers suggest that cryogenic arrays of sail membranes may be attractive for applications in new physics searches and distributed quantum sensing experiments.