Atomic vapor spectroscopy in integrated photonic structures

TL;DR

This paper demonstrates integrated photonic structures immersed in atomic vapor, enabling miniaturized alkali atom spectroscopy with tunable waveguide geometries and evanescent atom-light interactions, validated by experiments and simulations.

Contribution

It introduces a novel integrated chip platform for atomic vapor spectroscopy using silicon nitride waveguides and interferometers with flexible coupling methods.

Findings

Evanescent atom-light interactions match numerical simulations.

Waveguide geometries significantly influence vapor transmission.

The platform enables miniaturized and integrated atomic spectroscopy.

Abstract

We investigate an integrated optical chip immersed in atomic vapor providing several waveguide geometries for spectroscopy applications. The narrow-band transmission through a silicon nitride waveguide and interferometer is altered when the guided light is coupled to a vapor of rubidium atoms via the evanescent tail of the waveguide mode. We use grating couplers to couple between the waveguide mode and the radiating wave, which allow for addressing arbitrary coupling positions on the chip surface. The evanescent atom-light interaction can be numerically simulated and shows excellent agreement with our experimental data. This work demonstrates a next step towards miniaturization and integration of alkali atom spectroscopy and provides a platform for further fundamental studies of complex waveguide structures.