Microwave field amplitude stabilization using Ramsey spectroscopy signal

Abstract

We present a method to actively stabilize the amplitude of the microwave field which constitutes the probe for many state-of-the-art compact atomic clocks. The method applies to clocks working in pulsed operation, specifically with a Ramsey scheme. The proposed technique relies on information directly extracted from the clock atomic signal, as it computes the gradient in the two variables (amplitude and frequency) characterizing the probe field, instead of differentiating solely the frequency response, as in usual operation. Magnetic field sensing based on spectroscopy has proven to be a valuable tool for metrology and precise measurement field. We demonstrate the advantage of using the spectroscopic signal to stabilize the microwave field amplitude, in order to reach 10−15 stability with compact clocks, by mitigating cavity-pulling shift effects.