Measurement of the Effective Nonradiative Relaxation Rate near a Metallic Film

We have studied the effective nonradiative relaxation rate of the hyperfine level 87Rb[5P3/2(=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 ob() is the summation of the signal originating from the far-field region () and the signal originating from the near-field region (). Considering the thermalization of 87Rb(5P3/2) atoms in the far-field region, we can approximate () 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 ′=3→=2=2.3×108s−1 near the metallic film is relatively large compared to the spontaneous emission rate ′=3→=2=1.1×107s−