Double-resonance optical-pumping spectra of rubidium 5S1/2-5P3/2-4D3/2 transitions and frequency stabilization of 1.5-micrometer laser

We demonstrate the spectra of Rb-87 5S(1/2) - 5P(3/2) - 4D(3/2) transitions by utilizing the double-resonance optical-pumping (DROP) and optical-optical double-resonance (OODR) techniques, respectively. The DROP spectrum, compared with the traditional OODR spectrum, show a much better signal-to-noise ratio (SNR). Paying special attention to the influence of alignment of lasers where the coupling and probe beams are counter-propagation and co-propagation on DROP spectrum, so as to further narrow the spectral width by means of electromagnetically induced transparency (EIT). When -the frequency of 1.5 mu m fiber-pigtailed butterfly-type distributed-feedback (DFB) diode laser is stabilized to the DROP spectrum of Rb-87 5P(3/2) - 4D(3/2) transition, the preliminary result of residual frequency jitter after stabilization is similar to +/- 1.3 MHz within 60 s.