Chiral chaos–enhanced sensing

``Chirality'' refers to the property that an object and its mirror image cannot overlap each other by spatial rotation and translation. Chirality can be found in various research fields. Here we propose chiral chaos and design a chiral chaotic device using whispering gallery mode resonators and tips, where the routes to chaos exhibit pronounced chirality for two pumping directions. The mechanism underlying chirality is that time-reversal symmetry of traveling-wave light fields is regulated by tips, and chaos originates from the nonlinear optomechanical interactions. We propose metrics based on the Lyapunov exponents to quantify the symmetry and chirality between routes to chaos. We show that the proposed chiral chaotic device can be applied to achieve sensing with high sensitivity, a broad detectable range, and strong robustness regarding phase and orientation randomness of weak signals. Our work provides a promising candidate for on-chip sensing and may have applications in chaotic networks and chaotic communications.