Laser power dependence of rubidium two-photon transition spectra

拓馬 伊藤

Evan J. Carlson, Abraham J. Olson, Shannon K. Mayer

H. C. Busch, Christian Busch, Charles I. Sukenik

We describe a one-color, two-photon polarization spectroscopy experiment on the 5S1/2–5D5/2 transition in rubidium, suitable for implementation in an advanced undergraduate instructional laboratory. The proposed laboratory module synergistically combines polarization spectroscopy with established fluorescence detection at a wavelength different from the excitation wavelength. The curriculum provided in this paper allows students to compare experimental results with predicted theoretical lineshapes and to study the intensity dependence of the two-photon transition. The module also provides a springboard that enables instructors to expand the curriculum to incorporate additional measurements and theoretical analyses. These activities include collecting spectra on additional transitions, measuring the temperature dependence of the spectral amplitudes, or using the dispersive polarization spectra to frequency stabilize a laser without modulation.

Chuan Xie

Sandan Wang, Jinpeng Yuan, Lirong Wang +2 more

We experimentally study the high-resolution two-photon spectroscopy of rubidium using a single laser. The 5S1/2 − 5P3/2 − 5D5/2 transition is realized via 778.1 nm laser beams acting on the vapor with a counter-propagating configuration. The intensity modulation method is employed to improve the signal-to-noise ratio of the spectrum by two orders of magnitude compared with that for direct measurement. The effects of the vapor temperature, the frequency-scanning speed of the laser, the polarization combination of the laser beams, and the laser power on the spectra are investigated to obtain the optimal experimental parameters. This research is expected to be beneficial for potential applications since it can be used to realize a compact and high-precision frequency standard for optical communication.

Sandan Wang, Jinpeng Yuan, Lirong Wang +2 more

Abstract We report an experimental investigation of the 5 S 1/2 –7 S 1/2 one-color two-photon transition in rubidium vapor with a single continuous-wave laser operating at 760 nm. By utilizing a robust intensity modulation method, high-resolution spectra with a signal-to-noise ratio of ~120 are obtained. A perfect match between experimental results and the theoretical analysis is obtained by characterizing the probability of a two-photon transition with vapor temperature and laser power. Moreover, the influence of electric dipole selection rules on the two-photon transition is also investigated by changing the polarization of the laser beam. Since the 5 S 1/2 –7 S 1/2 two-photon transition is insensitive to stray magnetic fields and has an extremely narrow linewidth, we confidently believe that it can provide a concrete frequency standard for quantum telecommunication in the S -band window (1480–1530 nm). Meanwhile, the atomic system at 760 nm will serve as a good candidate for a quantum repeater.