Direct Calibration of Laser Intensity via Ramsey Interferometry for Cold Atom Imaging

Published

May 11, 2023

Author(s)

Emine Altuntas, Ian Spielman

Abstract

A majority of ultracold atom experiments utilize resonant absorption imaging techniques to obtain the atomic density. To make well-controlled quantitative measurements, the optical intensity of the probe beam must be precisely calibrated in units of the atomic saturation intensity Isat. In quantum gas experiments, the atomic sample is enclosed in an ultra-high vacuum system that introduces loss and limits optical access; this precludes a direct determination of the intensity. Here, we use quantum coherence to create a robust technique for measuring the probe beam intensity in units of Isat via Ramsey interferometry. This technique characterizes the ac Stark shift of the atomic levels due to an off-resonant probe beam. Furthermore, this technique gives access to the spatial variation of the probe intensity at the location of the atomic cloud. By directly measuring the probe intensity just before the imaging sensor our method in addition yields a direct calibration of imaging system losses as well as the quantum efficiency of the sensor.

Citation

Optics Express

Volume

31

Issue

11

Pub Type

Journals

Download Paper

https://doi.org/10.1364/OE.488710

Local Download

Keywords

atomic saturation intensity, sensor quantum efficiency, intensity inhomogeneities

Citation

Altuntas, E. and Spielman, I. (2023), Direct Calibration of Laser Intensity via Ramsey Interferometry for Cold Atom Imaging, Optics Express, [online], https://doi.org/10.1364/OE.488710, https://tsapps.nist.gov/publication/get_pdf.cfm?pub_id=936465 (Accessed October 8, 2025)