High-resolution 133Cs 6S-6D, 6S-8S two-photon spectroscopy using an intracavity scheme.

This Letter presents an intracavity scheme for diode laser based two-photon spectroscopy. To demonstrate generality, three (133)Cs hyperfine transition groups of different wavelengths are shown. For the 6S-6D transitions, we achieved a 10(2) times better signal-to-noise ratio than in previous work [J. Phys. Soc. Jpn. 74, 2487 (2005)] with 10(-3) times less laser power, revealing some previously vague and unobserved spectra. Possible mutual influences between the two-photon absorber and laser cavity were investigated for the first time to our knowledge, which leads to the application of a reliable hand-sized optical frequency reference. Our approach is applicable for most of the two-photon spectroscopy of alkali atoms.