Measurement of the Rb-87[5P(3/2)(F ' = 3) - 5S(1/2)(F = 2)] Effective Nonradiative Relaxation Rate near a Metallic Film

We have studied the effective nonradiative relaxation rate of the hyperfine level Rb-87[5P(3/2)(F' = 3)] near a metallic film with diode laser-induced retrofluorescence spectroscopy and saturated-absorption spectroscopy technique. The glass-vapor interface is considered as two distinct regions, a wavelength-thickness vapor layer joined to the surface and a more remote vapor region. The total experimental retrofluorescence signal Sob(nu(L)) is the summation of the signal originating from the far-field region ST (nu(L)) and the signal originating from the near-field region sn(nu(L)). Considering the thermalization of Rb-87(5P(3/2)) atoms in the far-field region, we can approximate S-T (nu(L)) by using the vertical fluorescence signal near the entrance window. Thus we get the experimental hyperfine signal profile of 87Rb in the near-field region. The value of the effective nonradiative transfer rate A(F'=3 -> F=2)(nf) = 2.3 x 10(8)s(-1) near the metallic film is relatively large compared to the spontaneous emission rate A(F'=3) (-> F=2) = 1.1 x 10(7)s(-1).