Orientation-sensed Optomechanical Accelerometers based on Exceptional Points

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 ${\alpha}\ll1$. 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.