Laser frequency stabilization using selective reflection from a vapor cell with a half-wavelength thickness

We have experimentally studied the selective reflection spectra of a circularly-polarized laser beam from a sub-micrometric Rb vapor cell with a thickness L around λ/2 (λ = 780 nm being the laser wavelength tuned to the D₂ line) in the presence of a longitudinal magnetic field. Based on the results of these studies, we propose a new method for the tunable locking of the diode laser frequency, which does not require frequency modulation nor complex electronics. The experimental realization of the technique has demonstrated its effectiveness and its competitiveness with the known DAVVL-type methods.