Optical Clock Based on Two-Photon Spectroscopy of the Nuclear Transition in a 229Th Ion in a Monochromatic Field
摘要
The possibility of two-photon laser spectroscopy of the nuclear clock transition (148.38 nm) in the 229Th isotope has been investigated using an intense monochromatic laser field at twice the wavelength (296.76 nm). Our estimates show that due to the electron bridge process in the doubly ionized ion 229Th2+ the sufficient intensity of a continuous laser field is about 10–100 kW/cm2, which is within the reach of modern laser systems. This unique possibility is an result of the presence in the electronic spectrum of the ion 229Th2+ of an exceptionally close intermediate (for the two-photon transition) energy level, forming a strong dipole (