We demonstrate a new type of high-resolution two-photon frequency modulation (FM) spectroscopy with cold atoms in a magneto-optical trap. Instead of modulating the probe as in ordinary FM spectroscopy, we modulate the trap itself by FM of the trapping beams. We present theoretical as well as experimental results for both absorption and polarization rotation spectroscopy. Finally, we demonstrate two-photon FM spectroscopy, using the intrinsic phase noise of the trapping diode lasers.
© 1998 Optical Society of America
J. L. Sørensen, J. Hald, and E. S. Polzik, "Spectroscopy on a modulated magneto-optical trap," Opt. Lett. 23, 25-27 (1998)