A method for determining a resonant frequency of an optically coupled resonator includes modulating an incident light and striking a laterally offset photodiode with the modulated incident light. An electric field is generated between the laterally offset photodiode and the resonator in response to the modulated incident light, and the resonator is driven with a driving component of the generated electric field. A reflected light from the resonator is sensed, and the resonant frequency of the resonator is determined based on the reflected light. A system for determining a resonant frequency of an optically coupled resonator and a method of sensing an applied stimulus are also disclosed.