Orientation-sensed Optomechanical Accelerometers based on Exceptional Points

Abstract

We propose an optomechanical design, consisting of a parity-time symmetric multilayer structure tuned at exceptional-point degeneracy (EPD), with an adjustable layer that is coupled to micromechanical springs. The deflections of this layer in response to accelerations $\alpha$, lead to square-root resonance detuning $\Delta \omega \equiv \omega -{\omega }_{EPD}\propto \sqrt{\alpha }$ - thus dramatically enhancing the probe of ultra-small accelerations $\alpha \ll 1$. Our design is scalable and can, in principle, support higher $N$ order EPDs with sensitivity $\Delta \omega \propto \sqrt[n]{\alpha }$. It also provides a pathway towards a new generation of on-chip hypersensitive accelerometers and vibrometers.