title: Laser frequency locking by direct measurement of detuning.
abstract: We present a new method of laser frequency locking in which the feedback signal is directly proportional to the detuning from an atomic transition, even at detunings many times the natural linewidth of the transition. Our method is a form of sub-Doppler polarization spectroscopy, based on measuring two Stokes parameters (I2 and I3) of light transmitted through a vapor cell. It extends the linear capture range of the lock loop by as much as an order of magnitude and provides frequency discrimination equivalent to or better than those of other commonly used locking techniques.
authors.affiliation: School of Physical Sciences, University of Queensland, St. Lucia 4072, Australia.
authors.forename: A
authors.initials: A
authors.lastname: Ratnapala
authors.forename: C J
authors.initials: CJ
authors.lastname: Vale
authors.forename: A G
authors.initials: AG
authors.lastname: White
authors.forename: M D
authors.initials: MD
authors.lastname: Harvey
authors.forename: N R
authors.initials: NR
authors.lastname: Heckenberg
authors.forename: H
authors.initials: H
authors.lastname: Rubinsztein-Dunlop