A sensor including a resonator comprising a nonlinear material comprising a nonlinear susceptibility configured to convert a pump electromagnetic wave (EM) wave to a signal EM wave and an idler EM wave, wherein at least one of the pump EM wave, the signal EM wave and/or the idler EM wave is fed back through the nonlinear material to form one or more resonant EM waves. An actuator coupled to the resonator or a pump path to the resonator, controls at least one of a pump power of the pump EM wave, a detuning of the frequency modes of the resonator relative to one or more frequencies of the resonant EM waves, or a phase matching of the nonlinear material. An output of the resonator outputs one or more output EM waves comprising information about a sample coupled to the resonator.