Rubidium spectroscopy with 778- to 780-nm distributed feedback laser diodes
Anselm J. Deninger, Sebastian Kraft, Frank Lison +1 more
Distributed feedback (DFB) laser chips have recently become available at wavelengths that match the D1 and D2 resonance transitions of alkaline atoms. We investigated the spectral properties, tuning characteristics and modulation behavior of continuous wave, single-mode DFB diodes at 778-780 nm and performed high-resolution spectroscopy of Rubidium vapor. The mode-hop free tuning range of the DFB diodes was as large as 2.4 nm (1186 GHz). The line width of the laser diodes was examined both with a heterodyne beat experiment and with high-resolution Doppler-free two photon spectroscopy, yielding a half width of 2-2.5 MHz. The saturation spectra of the D2-line of 85Rb and 87Rb were recorded with a resolution close to the natural line width. The emission frequency was actively stabilized to Doppler-free transitions with a relative accuracy of better than 4 parts in 109 using commercially available servo devices only. The output power of 80 mW was sufficient to allow for two photon spectroscopy of the 5S-5D-transition of 87Rb. We conclude that the performance of the DFB laser equals that of grating-stabilized external-cavity diode lasers (ECDLs), without the mechanical complexity of the latter systems. The DFB diode is thus well-suited to high-resolution applications in alkaline spectroscopy, including laser cooling and optical manipulation of ultra-cold atoms.
Proceedings of SPIE, the International Society for Optical Engineering/Proceedings of SPIE•Apr 28, 2005•2 citations