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Title: Direct calibration of laser intensity via Ramsey interferometry for cold atom imaging

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 intensityIsat. 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 ofIsatvia 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.

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Award ID(s):
Author(s) / Creator(s):
Publisher / Repository:
Optical Society of America
Date Published:
Journal Name:
Optics Express
1094-4087; OPEXFF
Page Range / eLocation ID:
Article No. 17893
Medium: X
Sponsoring Org:
National Science Foundation
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