Selective reflection from Rb vapor in half- and quarter-wave cells: Features and possible applications

The features of the effect of selective reflection from rubidium vapor in a nanocell with the thickness L ae lambda/2 and L ae lambda/4, where lambda = 795 nm is the wavelength of laser radiation resonant with the Rb D (1) line, are studied. It is shown that, because of the behavior of the nanocell as a low-Q-factor Fabry-P,rot etalon, the sign of the derivative of the selective reflection spectra changes near L ae lambda/2 from negative at L > lambda/2 to positive at L < lambda/2. The simplicity of the experimental implementation, large amplitude, and sub-Doppler width (40MHz) of a detected signal at an atomic transition frequency are appropriate for applications in metrology and magnetometry. In particular, selective reflection from the nanocell is a convenient frequency marker of atomic transitions; in this case, the amplitudes of peaks are proportional to the transition probabilities. The remote optical monitoring of a magnetic field with a spatial resolution L = lambda/4 ae 199 of nm is possible on the basis of the splitting of selective reflection peaks in a strong magnetic field (up to 3 kG). A theoretical model describes well the experimental results.