title: Atom-Based Sensing of Weak Radio Frequency Electric Fields Using Homodyne Readout.
abstract: We utilize a homodyne detection technique to achieve a new sensitivity limit for atom-based, absolute radio-frequency electric field sensing of 5 μV cm-1Hz-1/2. A Mach-Zehnder interferometer is used for the homodyne detection. With the increased sensitivity, we investigate the dominant dephasing mechanisms that affect the performance of the sensor. In particular, we present data on power broadening, collisional broadening and transit time broadening. Our results are compared to density matrix calculations. We show that photon shot noise in the signal readout is currently a limiting factor. We suggest that new approaches with superior readout with respect to photon shot noise are needed to increase the sensitivity further.
authors.affiliation: Homer L. Dodge Department of Physics and Astronomy, The University of Oklahoma, 440W. Brooks St. Norman, OK 73019, USA.
authors.forename: Santosh
authors.initials: S
authors.lastname: Kumar
authors.affiliation: Homer L. Dodge Department of Physics and Astronomy, The University of Oklahoma, 440W. Brooks St. Norman, OK 73019, USA.
authors.forename: Haoquan
authors.initials: H
authors.lastname: Fan
authors.affiliation: Physikalisches Institut, Universit¨at Stuttgart, Pfaffenwaldring 57 D-70550 Stuttgart, Germany.
authors.forename: Harald
authors.initials: H
authors.lastname: Kübler
authors.affiliation: Homer L. Dodge Department of Physics and Astronomy, The University of Oklahoma, 440W. Brooks St. Norman, OK 73019, USA.
authors.forename: Jiteng
authors.initials: J
authors.lastname: Sheng
authors.affiliation: Homer L. Dodge Department of Physics and Astronomy, The University of Oklahoma, 440W. Brooks St. Norman, OK 73019, USA.
authors.forename: James P
authors.initials: JP
authors.lastname: Shaffer