The main activity within this project will focus on the study of Double Resonance (DR) and Coherent Population Trapping (CPT) spectroscopy in wall-coated alkali vapour cells. This choice is motivated by the fact that wall coated cells represent a promising alternative to miniaturized buffer-gas cells for improved resolution in applications.
To aim towards the long-term goal of miniaturized (mm- or micro-m-scale) wall-coated cells, we pursue the following project goals: 1) to understand of the limitations in today’s state-of-the-art miniature cells containing buffer gases, by experimental studies using DR and CPT spectroscopy; 2) to understand how the atomic relaxation processes and resonance signals are affected by the presence of the wall coating in cm-scale cells, by using e.g. DR spectroscopy; 3) to understand the atom-light interactions of relevance for DR and CPT in wall-coated cells, in order to obtain narrow and high-contrast resonance signal that can be exploited in novel atomic frequency standards and other precision instrumentation. In particular, the role of laser linewidth for CPT in coated cells will be addressed. Evaluate effects that will shift the resonance frequency; 4) to evaluate selected spectroscopic schemes and reference signals from wall-coated cells in actual DR-based and CPT-based atomic clock setups. This will result in the first direct stability measurements performed for atomic clocks using wall-coated cells. From the narrow resonance linewidths we expect short-term clock stabilities around 1x10-13 Tau –1/2 or better (1x10-14 Tau –1/2 for shot-noise limited operation). On all these lines, a strong focus of the work will be devoted to investigate the interactions that are expected to affect the resonance signal when passing from cm-scale cells to micro-m-scale cells, being of high relevance for the development of miniaturized atomic frequency standards and atomic magnetometers.
Potential applications
The project will also contain a prospective part on possible applications of the obtained results which is strongly correlated with the other parallel activities in LTF: (1) high-performance vapour-cell-atomic clock for navigation and in view of a super Local Oscillator for primary standards (< 1x10-13 Tau –1/2 stability); (2) compact CPT-atomic clocks. As a long-term goal, the realisation and study of wall-coated miniature cells is envisaged.