Selective reflection from an Rb layer with a thickness below λ/12 and applications

We have studied the peculiarities of selective reflection from an Rb vapor cell with a thickness L < 70 nm, which is smaller than the length scale of evanescent fields lambda/2 pi and more than an order of magnitude smaller than the optical wavelength. A 240 MHz redshift due to the atom-surface interaction is observed for a cell thickness of L = 40 nm. In addition, complete frequency-resolved hyperfine Paschen-Back splitting of atomic transitions to four components for Rb-87 and six components for 87Rb is recorded in a strong magnetic field (B > 2 kG). (C) 2017 Optical Society of America