Absolute frequency determination of the 5P_3/2-->7S_1/2 transition in ^87Rb

Abstract

We report the absolute frequency of the important 5S(1/2)-->7S(1/2) two-photon transition in (87)Rb. We access the upper state using two dipole-allowed transitions via the intermediate 5P(3/2) state. This allows us to use much lower laser intensities compared to directly driving the two-photon transition, thereby avoiding potential errors due to the AC Stark shift. Collisional shifts are also minimized because the atomic density required is several orders of magnitude smaller. Our values are consistent with earlier frequency-comb measurements.

Absolute frequency measurement of rubidium 5S–7S two-photon transitions

“…Comparisons presented in Fig. 6 and Table 3 show that, while there is a good agreement with all previous measurements of the A hyperfine constants and isotope shift of the 5S-7S transition, the absolute frequency measurements agree within the expanded uncertainties only with the values given in [2][3][4]; whereas, all transition frequency measurements in [5] are systematically higher that those measured in [2], where the measurement scheme was similar to ours. Since the measurements of the hyperfine and isotope structures are not absolute, but relative, the discrepancy between Ref.…”

“…That technique and good long-term stability of our system reduce the statistical uncertainties of measured frequencies below 1 kHz, an order of magnitude better than in Refs. [2][3][4], thanks to the longer averaging times. The low statistical uncertainty enabled studies of systematic shifts with accordingly higher precision.…”

“…The digital lock, a technique generally used in optical atomic clocks, allows for long interrogation of the nonmodulated reference beam with an optical frequency comb. That technique, and the good long-term stability of our system, reduce the statistical uncertainties of measured frequencies below 1 kHz, an order of magnitude better than in [2][3][4], thanks to the longer averaging times. The low statistical uncertainty enables studies of systematic shifts with accordingly higher precision.…”

“…The ac-Stark effect in the 5S-7S transition is also smaller than in the 5S-5D case. Because of the difference in the signal strengths, all previous measurements of the 5S-7S transition [2][3][4][5] yielded absolute values of its frequency that were less accurate than for the 5S-5D transition [6][7][8][9]. In this Letter, we report the absolute frequency measurements for the 5S 1∕2 -7S 1∕2 transitions in 87 Rb and 85 Rb, with relative standard uncertainty less than 10 −11 , which is better than previously measured and comparable to measurements of the 5S-5D transition [6].…”

Narrow-linewidth double-resonance optical pumping spectrum due to electromagnetically induced transparency in ladder-type inhomogeneously broadened media

“…The spectra between the excited states with the natural characteristic of being Doppler-free due to the velocity-selective mechanism have been used in high-resolution spectroscopy, laser frequency stabilization, frequency references in optical communication, and precision measurement [1][2][3][4]. The excited spectra can be usually acquired by the optical-optical double resonance (OODR) technique, but sometimes they have low signal-tonoise ratios (SNRs) [5].…”