Cavity-Enhanced Non-destructive Measurement of Magnetic Observables in Cold Atomic Ensembles

Abstract

Faraday rotation measurements (FRM) are highly valuable due to their potential to behave as quantum non-destructive measurements under certain conditions. Moreover, applying FRM to Bose-Einstein condensates (BEC) offers significant insights into the magnetic properties, dynamics, and quantum phenomena of the condensate. To optimize FRM on a BEC, we have implemented an optical cavity that maximizes the interaction between atoms and light. In this work we present a frequency locking system for a 780nm probe laser implementing a Maximum Search Algorithm in a microcontroller Arduino UNO. The implementation of this system has yielded promising results, reducing the noise after the cavity by ∼ 20dB compared to the system without the algorithm. Consequently, we can approach the shot noise limit more closely, stabilizing the set-up for the Faraday rotation measurements.