Abstract：The signals of the hyperfine 85Rb[5P3/2(F′=2，3，4)→5S1／2(F＝3)] transition lines in a diode laser induced retrofluorescence spectrum at the interface between glass and Rb vapor were experimentally identified and investigated. The glass-vapor interface was considered as two distinct regions, a wavelength-thickness vapor layer joined to the surface and a more remote vapor region. The first region was analyzed as a spectral filter that annihilates the absorbed photons and the second one as a rich spectral light source. The experimental setup is described. A Rb reference cell (T=293 K) was used. A part of the laser beam scanned the 5S1／2(F＝3)→5P3／2(F′＝2，3，4) transition. The Doppler broadened absorption profile (FWHM=510 MHz) was determined. The laser detuning of the profile-center relative to the F=3→F′＝4 transition was about 70 MHz. Another laser beam was directed to the entrance cell window. The resonant retrofluorescence Sob(νL) as a function of laser detuning for a cell temperature ～130 ℃ and laser power 0.4 mW was obtained. We can extract the experimental signal snexP(νL) originating from the near-field region by subtracting signal ST(νL) originating from the far-field region from the total experiment signal Sob(νL). A fit of the normalized profile of the data corresponding to the spectral band centered on the F′＝4→F＝3 hyperfine transition line was obtained by using a Lorentzian distribution function with ΓRF＝50 MHz full width at half-maximum. The role played by different relaxation processes contributing to the retrofluorescent atomic linewidth was characterized. The authors summed up the corresponding spectral broadening and obtained the relation ΓRF＝Γn+Γcoll+Γnr,where Γcoll is the resonance collisional broadening of the hyperfine line, and Γnr is an additional broadening induced by the nonradiative energy-transfer phenomena of the excited atoms near the cell window surface. To evaluate Γcoll,we used the relation Γcoll＝γRb-RbN, where γRb-Rb is line broadening parameter, and N is Rb atom number density. The effective nonradiative relaxation rate of the 5P3／2(F′＝4) energy hyperfine level was estimated to be AnrF′＝4→F＝3＝2.4×108s-1. The value of Anr seems relatively large compared to the spontaneous emission rate A(5P3/2→5P1/2)＝1.4×107s-1.
刘静1,2,辛璟焘1,戴康1,沈异凡1*. 利用激光诱导后向荧光测定Rb[5P3/2(F′＝4)]在金属膜附近的非辐射跃迁率[J]. 光谱学与光谱分析, 2009, 29(01): 6-9.
LIU Jing1,2,XIN Jing-tao1,DAI Kang1,SHEN Yi-fan1*. Measurement of the Rb[5P3/2(F′=4)] Hyperfine Level Nonradiative Decay Rate Near a Metallic Film with Laser Retrofluoresence Spectroscopy. SPECTROSCOPY AND SPECTRAL ANALYSIS, 2009, 29(01): 6-9.
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