Frequency locked micro disk resonator for real time and precise monitoring of refractive index

Abstract:

We experimentally demonstrate a frequency modulation locked servo loop, locked to a resonance line of an on-chip microdisk resonator in a silicon nitride platform. By using this approach, we demonstrate real-time monitoring of refractive index variations with a precision approaching 10−7  RIU, using a moderate Q factor of 104. The approach can be applied for intensity independent, dynamic and precise index of refraction monitoring for biosensing applications.