The hyperfine structure of the ${}^{2}{S}_{1/2}{\ensuremath{-}}^{2}{D}_{5/2}$ quadrupole transition at 674 nm in
87Sr+ has been observed. The ion was confined in a Paul trap and cooled using laser radiation at 422 and 1092 nm. The quadrupole transition was observed by monitoring quantum jumps in the 422-nm fluorescence. The odd isotope of strontium has ``clock'' transitions independent of the first-order Zeeman shift and the
2D5/2 state hyperfine structure constants have been determined as
AD5/2=2.1743(14)MHz and
BD5/2=49.11(6)MHz. Standard uncertainties have been added in parentheses. These values allow the second-order Zeeman shifts to be calculated. The ${}^{88}{\mathrm{Sr}}^{+}{\ensuremath{-}}^{87}{\mathrm{Sr}}^{+}$ isotope shift for the 674-nm quadrupole transition has been measured to be 247.99(4) MHz.
We report the first observation to our knowledge of the 6s2 S10-6s6p P11∘ transition (398.8 nm) of 168Yb. The relative position of this spectral line was directly determined by using a laser sideband technique to simultaneously probe pairs of lines. The hyperfine structure of 171Yb and the isotope shifts of 170Yb, 171Yb, and 174Yb were determined to an accuracy of better than 6 MHz and found to differ by as much as 23 MHz from previous results. By using photon-burst spectroscopy to carry out these measurements we obtained subnatural linewidths and fully resolved the 170Yb and 171Yb lines, which otherwise overlap in fluorescence.
Compared to other stable isotopes of
Yb+,
173Yb+ has a richer hyperfine structure, which leads to more favorable clock transitions, spectroscopic techniques for probing new physics, and more sophisticated quantum computing architectures. However, to date, its electronic spectrum remains poorly characterized. Here, we report on efficient laser cooling, state preparation, and detection of a single trapped
173Yb+ ion. The previously unobserved
2S1/2→2D3/2 electric quadrupole transition at 436 nm is coherently excited, and the isotope shift between
171Yb+ and
173Yb+ on this transition is determined with an uncertainty of 1.4 Hz. Using microwave spectroscopy, we resolve the hyperfine structure (HFS) of the
2D3/2 state with a relative uncertainty below
10−8. From the HFS measurement data, we infer for
173Yb a nuclear magnetic octupole moment
Ω=−0.062(8)(b×μN) with uncertainty reduced by more than 2 orders of magnitude compared to previous studies. The data also allow us to determine hyperfine anomalies for the
2S1/2 and
2D3/2 states.
We have measured and analyzed the hyperfine structure of two lines, one at 583 nm and one at 401 nm, of the only stable fermionic isotope of atomic erbium as well as determined its isotope shift relative to the four most-abundant bosonic isotopes. Our work focuses on the $J\ensuremath{\rightarrow}J+1$ laser cooling transitions from the
[Xe]4f126s2(3H6) ground state to two levels of the excited
[Xe]4f126s6p configuration, which are of major interest for experiments on quantum degenerate dipolar Fermi gases. From a fit to the observed spectra of the strong optical transition at 401 nm we find that the magnetic dipole and electric quadrupole hyperfine constants for the excited state are ${A}_{e}/h=\ensuremath{-}100.1(3)\phantom{\rule{0.28em}{0ex}}\mathrm{MHz}$ and ${B}_{e}/h=\ensuremath{-}3079(30)\phantom{\rule{0.28em}{0ex}}\mathrm{MHz}$, respectively. The hyperfine spectrum of the narrow transition at 583 nm, was previously observed and accurate
Ae and
Be coefficients are available. A simulated spectrum based on these coefficients agrees well with our measurements. We have also determined the hyperfine constants using relativistic configuration-interaction ab initio calculations. The agreement between the ab initio and fitted data for the ground state is better than 0.1%, while for the two excited states the agreement is 1% and 11% for the
Ae and
Be constants, respectively.
Doppler-free saturated absorption spectroscopy is performed on an enriched radioactive
39Ar sample. The spectrum of the
3s23p54s[3/2]2--
3s23p54p[5/2]3 cycling transition at 811.8 nm is recorded, and its isotope shift between
39Ar and
40Ar is derived. The hyperfine coupling constants
A and
B for both the
4s[3/2]2 and
4p[5/2]3 energy levels in
39Ar are also determined. The results partially disagree with a recently published measurement of the same transition. Based on earlier measurements as well as the current work, the isotope shift and hyperfine structure of the corresponding transition in
37Ar are also calculated. These spectroscopic data are essential for the realization of laser trapping and cooling of
37,39Ar.
Hyperfine splittings for the 39 K and 41 K isotopes and the isotope shift for the 4s 2 S 1/2 → 6s 2 S 1/2 two-photon transition have been measured using sub-Doppler fluorescence spectroscopy. We have accurately measured the transition isotope shift, and a discrepancy has been found in the earlier reported transition isotope shift value, which has been corrected. The resulting hyperfine splitting values of 418.2 (5) and 230.4 (1.3) MHz for the 39 K and 41 K isotopes respectively are in agreement with previous measurements. The precision of the absolute frequency values for the two-photon transition has been improved by about two orders. Our measured magnetic dipole constants for the upper 6 2 S 1/2 state for the 39 K and the 41 K isotopes are consistent with the earlier measured values.