Velocity Transfer Spectroscopy of Rb 420 nm Transition

We propose and demonstrate the velocity transfer spectroscopy of a V-type energy structure with Rb atoms at 420nm transition. The weak oscillator strength of a lower excited state for V-type energy structure atoms limits the high signal-to-noise ratio of atomic laser spectroscopy, which can be usually realized by optical-optical double-resonance or double-resonance optical pumping for cascade-type energy structure atoms. For ^87Rb atoms, the weak 420 nm transition spectrum between the energy level of 5^2S1/2 and 6^2P3/2 is transferred to the spectrum on lower excited states at 780nm with strong oscillator strength, which is recorded by a 780 nm probe laser. This method, which ＆ similar to the electron-shelving detection method, at a certain degree can indirectly measure a higher excited state transition with weak oscillator strength for any V-type energy structure of atoms by transferring the transition spectrum information of the very weak oscillator strength to the strong oscillator strength in an optical-optical double-resonance configuration.     

Laser 728 nm Spectroscopy of Electrodeless Discharge Rb Lamp

The electrodeless discharge rubidium vapor lamp plays a key role in a number of applications, such as atomic clock, atomic magnetometer, atomic optical filter and laser frequency stabilization. The electrodeless discharge Rb vapor lamp has rich spectra, including 420nm, 421nm, 565nm, 572nm, 607nm, 616nm, 728 nm, 776 nm, 780 nm, 795 nm, 1324 nm, 1344 nm, 1366 nm, 1475 nm, 1529 nm spectroscopy, etc. The 780nm transition wavelength between 5P3/2 and 5S1/2 of Rb atoms is usually used in fields of the Rb atomic clock and the Rb atomic magnetometer.With the 421.7 nm laser pumping atoms from 5S1/2 to 6P1/2, 1366.9 nm transition from 6S1/2 to 5P3/2 can be used as a clock transition of Rb four levels for an atomic active optical clock. An active optical clock is a new conception of the atomic clock and has the potential to improve the stabil- ity of the best atomic clocks by about two orders of magnitude. Another application of the elec- trodeless discharge Rb vapor lamp is the Rb Faraday anomalous-dispersion optical filter （FADOF） （e.g., 776 nm] and 1529 nm spectroscopy）, in which the electrodeless discharge Rb vapor lamp is more feasible than the one using a laser pumped Rb vapor cell in some cases, since many excited states are populated enough for aimed FADOF transition. Although the rich spectra of Rb have many applications, so far no detailed investigations or applications have been achieved in 728.0nm transition. To the best of our knowledge, the Rb 728.0 nm spectral data are currently only from the fluorescence by Beacham arc spectrum of rubidium early in 1959.     

Cs 728 nm Laser Spectroscopy and Faraday Atomic Filter

The laser spectroscopy of alkali-metal vapor is widely used in a number of applications, such as the Faraday anomalous dispersion optical fil- ter （FADOF）, the active optical clock, and wavelength references.Is＇ The Cs electrodeless dis- charge vapor lamp has rich spectra, including 455 nm, 459 nm, 728 nm, 852 nm, 1359 nm, and 1470 nm. The 852 nm laser pumping atoms from 6S1/2 to 6P3/2 have been used in FADOF.The 1359nm wave- length transited from 7S1/2 to 6P1/2 of Cs atoms can be used in the field of active optical clocks. The concept of active optical clocks has been proposed since 2005. Due to its good performance in sta- bility, the active optical clock has been extensively in- vestigated theoretically and experimentally in recent years, such as the two-level active optical clock, and three-level active optical clock. When considering the performance of the active optical clock, we hope to reduce the second-order Doppler shift in thermal atomic beam and the light shift induced by the pump- ing laser. To solve this issue, our group has recently proposed a four-level active optical clock, such as K 1252.2nm, Cs 1469nm, Rb 1366.9nm and Rb 728 nm. Moreover, the Rb 728 nm four-level quantum system has potentially a better performance than three long wavelength ones of Rb.