相关论文: Absolute frequency measurement of the magnesium in…
We apply direct frequency-comb spectroscopy, in combination with precision cw spectroscopy, to measure the ${\rm 4s4p} ^3P_1 \to {\rm 4s5s} ^3S_1$ transition frequency in cold calcium atoms. A 657 nm ultrastable cw laser was used to excite…
We report the direct frequency measurement of the visible 5s$^2$ $^1$S$_0$-5s 5p$^3$P$_1$ intercombination line of strontium that is considered a possible candidate for a future optical frequency standard. The frequency of a…
The frequency of the Calcium ^3P_1--^1S_0 intercombination line at 657 nm is phase-coherently measured in terms of the output of a primary cesium frequency standard using an optical frequency comb generator comprising a sub-10 fs Kerr-lens…
We have performed for the first time direct laser spectroscopy of the 1S0-3P0 optical clock transition at 265.6 nm in fermionic isotopes of neutral mercury laser-cooled in a magneto-optical trap. Spectroscopy is performed by measuring the…
We experimentally investigate an optical frequency standard based on the $^2S_{1/2} (F=0)\to {}^2F_{7/2} (F=3)$ electric octupole (\textit{E}3) transition of a single trapped $^{171}$Yb$^+$ ion. For the spectroscopy of this strongly…
In this paper we report the evaluation of an optical lattice clock based on neutral mercury down to a relative uncertainty of $1.7\times 10^{-16}$. Comparing this characterized frequency standard to a Cs atomic fountain we determine the…
We have measured the 1S - 2S transition frequency in atomic hydrogen via two photon spectroscopy on a 5.8 K atomic beam. We obtain $f_{1S-2S} = 2 466 061 413 187 035 (10)$ Hz for the hyperfine centroid. This is a fractional frequency…
We describe a measurement of the frequency of the 2S1/2(F = 0) - 2D3/2(F' = 2) transition of 171Yb+ at the wavelength 436 nm (frequency 688 THz), using a single Yb+ ion confined in a Paul trap and two caesium fountains as references. In one…
We report on the first absolute transition frequency measurement at the 10^{-15} level with a single, laser-cooled 40Ca+ ion in a linear Paul trap. For this measurement, a frequency comb is referenced to the transportable Cs atomic fountain…
We measured the absolute frequency of the optical clock transition 1S0 (F = 1/2) - 3P0 (F = 1/2) of 171Yb atoms confined in a one-dimensional optical lattice and it was determined to be 518 295 836 590 863.5(8.1) Hz. The frequency was…
Atom interferometry on optical clock transitions is being pursued for numerous long-baseline experiments both terrestrially and for future space missions. Crucial to meeting these experiments' required sensitivities is the implementation of…
We report a frequency measurement of the clock transition of a single ^40Ca^+ ion trapped and laser cooled in a miniature ring Paul trap with 10^-15 level uncertainty. In the measurement, we used an optical frequency comb referenced to a…
By varying the density of an ultracold $^{88}$Sr sample from $10^9$ cm$^{-3}$ to $> 10^{12}$ cm$^{-3}$, we make the first definitive measurement of the density-related frequency shift and linewidth broadening of the $^1S_0$ - $^3P_1$…
We present an experimental determination of the $4 \: S_{1/2} \rightarrow 6\: S_{1/2}$ transition frequency in atomic potassium, $^{39}$K, using direct frequency comb spectroscopy. The output of a stabilized optical frequency comb was used…
The pursuit of ever more precise measures of time and frequency is likely to lead to the eventual redefinition of the second in terms of an optical atomic transition. To ensure continuity with the current definition, based on a microwave…
We have measured the frequency of the $6s^2S_{1/2} - 5d^2D_{3/2}$ electric-quadrupole transition of $^{171}$Yb$^+$ with a relative uncertainty of $1\times 10^{-14}$, $\nu_{Yb}$ = 688 358 979 309 312 Hz $\pm$ 6 Hz. A femtosecond frequency…
We present the accurate measurement of the frequency of the $7S-7P$ laser-trapping transition for three francium isotopes. Our approach is based on an interferometric comparison to deduce the unknown laser frequency from a secondary laser…
We report the absolute frequency measurement of the unperturbed transition 1S0 - 3P0 at 578 nm in 171Yb realized in an optical lattice frequency standard. The absolute frequency is measured 518 295 836 590 863.55(28) Hz relative to a…
We report an uncertainty evaluation of an optical lattice clock based on the $^1S_0\leftrightarrow^3P_0$ transition in the bosonic isotope $^{174}$Yb by use of magnetically induced spectroscopy. The absolute frequency of the…
This article reports the first optical frequency measurement of the $1\mathrm{S}-3\mathrm{S}$ transition in hydrogen. The excitation of this transition occurs at a wavelength of 205 nm which is obtained with two frequency doubling stages of…