Direct calibration of laser intensity via Ramsey interferometry for cold atom imaging
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. Our 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.
Document Details
- Document Type
- Pub Defense Publication
- Publication Date
- May 11, 2023
- Source ID
- 10.1364/oe.488710
Entities
People
- Emine Altuntas
- Ian B. Spielman
Organizations
- Air Force Office of Scientific Research
- National Institute of Standards and Technology
- National Science Foundation
- University of Maryland