Optical-rf Double Resonance Research Articles

Individual Addressing of Trapped Ions and Coupling of Motional and Spin States Using rf Radiation

Individual electrodynamically trapped and laser cooled ions are addressed in frequency space using radio-frequency radiation in the presence of a static magnetic field gradient. In addition, an interaction between motional and spin states induced by an rf field is demonstrated employing rf optical double resonance spectroscopy. These are two essential experimental steps towards realizing a novel concept for implementing quantum simulations and quantum computing with trapped ions.

Coherent population trapping in an rf-optical double resonance experiment in a neon discharge

We observed radio-frequency (rf) induced transparency for a probe optical field in an rf-optical double resonance experiment in a neon discharge. The origin of the transparency is coherent population trapping at Zeeman sublevels of the lower level of an optical transition of neon. Stokes and anti-Stokes optical fields were generated due to stimulated Raman scattering of both the radio-frequency field on the probe-induced optical coherence and the probe field on the Zeeman coherence.

Nature of the Inhomogeneous Broadening of Optical Spectra in Eu3+doped Y2O3Crystals Studied by Optical-RF Double Resonance

The nature of the inhomogeneous broadening of optical spectra has been investigated for Eu 3+ ions embedded in pure and impurity ion (Sc 3+ or Zr 4+ ) doped Y 2 O 3 crystals. High-resolution absorption spectra of the 7 F 0 – 5 D 0 transitions have been taken as excitation spectra of luminescence. Using optical-radio-frequency (rf) double resonance technique, the distribution of two hyperfine transitions (ω 1 : I z =±1/2 to ±3/2 and ω 2 : I z =±3/2 to ±5/2) in the 7 F 0 ground state were measured as a function of the optical excitation energy and displayed as a 2-dimensional map on the optical and rf axes. Thus the ionic sites are labeled by three parameters and some new sites were distinguished by using both ω 1 and ω 2 . The single crystals with a disorder systematically controlled by doping of various ions (Sc 3+ and Zr 4+ ) were investigated and the character of the inhomogeneous distribution was found to be strongly dependent on the doped ions. By applying the mapping method to the Sc 3+ doped Y 2 O 3 , the individual sites are discriminated inside the inhomogeneously broadened optical spectra, while the discrete peaks coalesce into a single broad peak in the optical spectrum at higher concentration.

Hyperfine interaction in ground and excited states of praseodymium-doped yttrium orthosilicate

We present characterization of the hyperfine interaction for the ground ${(}^{3}{H}_{4})$ and one optically excited state ${(}^{1}{D}_{2})$ of praseodymium impurities in a yttrium orthosilicate crystal. The Zeeman and pseudoquadrupole tensors were inferred by measuring the hyperfine splittings while rotating the direction of a weak $(\ensuremath{\sim}40 \mathrm{G})$ magnetic field. The hyperfine spectra were recorded using Raman-heterodyne spectroscopy, a rf-optical double resonance technique.

Observation of sub-kilohertz resonance in Rf-Optical double resonance experiment in rare earth ions in solids

We have observed kilohertz and sub-kilohertz resonance structures in RF-optical double resonance experiments of rare-earth-doped solids, when the frequency of the RF ® eld is scanned across the hyper® ne transitions while monitoring the resonant optical absorption of a CW laser. The ea ect is observed only when the laser spectral width is broad compared to the hyper® ne structure. The observed line widths are apparently free of the inhomogeneous widths of hyper® ne levels and the line shape has peculiar double peak structure. The ea ect is modelled with a resonance involving three atomic levels interacting with three electromagnetic ® elds, two optical and one RF, in a triangular ordelta' con® guration. While the ordinary optical- RF two-® eld resonance is limited by spin inhomogeneous width, the simul- taneous excitation of three coupled transitions leads to narrow and highly nonlinear resonance structures that are not averaged by the inhomogeneous distribution of hyper® ne transition. We have observed a peculiarly narrow resonance structure in the course of optical-RF double resonance experiment of rare earth ions in solids. The reso- nance is characterized by a sharp doublepeak structure in the absorption spectrum as the RF frequency is scanned across the hyper® ne transition, with the few kilohertz width of the transparency hole at least an order of magnitude narrower than the spin inhomogeneous width. The ea ect is evident only when the laser bandwidth is larger than the hyper® ne level splittings. A theoretical model is presented based on the assumption that the optical ® elds of a noisy laser simul- taneously couples an optically excited state with two hyper® ne levels of the ground state, which in turn are acted on by the RF ® eld. A quantum interference ea ect among the three coupled transitions creates sharp fringes in the frequency domain that are not averaged out by ensemble average over the inhomogeneousbroadening of the optical or spin transitions. The model is found to be consistent with the main features of the experimental observations. Various quantum interference ea ects in atomic transitions have recently been research topics of great interest, because of the rich and often counter-intuitive

Observation of sub-kilohertz resonance in Rf-optical double resonance experiment in rare earth ions in solids

We have observed kilohertz and sub-kilohertz resonance structures in RF-optical double resonance experiments of rare-earth-doped solids, when the frequency of the RF field is scanned across the hyperfine transitions while monitoring the resonant optical absorption of a CW laser. The effect is observed only when the laser spectral width is broad compared to the hyperfine structure. The observed line widths are apparently free of the inhomogeneous widths of hyperfine levels and the line shape has peculiar double peak structure. The effect is modelled with a resonance involving three atomic levels interacting with three electromagnetic fields, two optical and one RF, in a triangular or “delta’ configuration. While the ordinary optical-RF two-field resonance is limited by spin inhomogeneous width, the simultaneous excitation of three coupled transitions leads to narrow and highly nonlinear resonance structures that are not averaged by the inhomogeneous distribution of hyperfine transition.

Three-parameter mapping of site distribution by optical-RF double resonance in Eu 3+ : Y 2O 3 crystals

Weak satellite lines were found in the optical excitation spectra of the Eu 3+ 7 F 0– 5 D 0 in Eu 3+ : Y 2O 3 crystals (undoped, Sc 3+ doped and Zr 4+ doped). Optical-RF double resonance of the ground state are reported for the main and satellite lines of undoped and Sc 3+ doped Eu 3+ : Y 2O 3. In the inhomogeneous broadening for both the main and satellite, the RF resonance corresponding to transition of I z=± 3 2 –± 1 2 increased with increasing the optical frequency with a rate of +10 kHz/GHz but RF resonance of I z=± 5 2 –± 3 2 did not dependent on the optical frequency. We could map site distribution on RF-optical axes and identify the site with three parameters (optical and two RF frequencies). Additional sites in Sc 3+-doped crystal were found in the site mapping.

Resolved isotopic energy shift and hole burning in EuCl 36H 2O

The 7F 0→ 5D 0 transition in EuCl 36H 2O is exceedingly narrow ∼0.5 GHz and exhibits partially resolved hyperfine splittings. Further, using EuCl 36H 2O crystals with different 151Eu : 153Eu isotope mixtures there is evidence of an isotope shift. Optical-RF double-resonance and burn-and-scan laser experiments employing the hole-burning behaviour of this transition support the analysis of the optical spectra.

Studies of rotational level Λ-doubling by rf-optical double resonance spectroscopy: application to NaK D1Π

We report here the application of optical-radio frequency double resonance spectroscopy for individual rotational levels of the NaK D 1 Π state. Lambda doubling constant q values for five ν′, J′ levels are obtained. These data are combined with measurements of dc e- f Stark-mixing-induced changes in optical spectra, and the electric dipole moment d p in the D 1 Π state is determined.

Spectroscopy of RE3+ Centers in Fluorite Host Using High Resolution Optical Hole-Burning and Double Resonance Techniques

Abstract Techniques of Optical Hole-burning, Optical-MW and Optical-RF Double Resonance have been used to study Ho3+ and Pr3+ in several trigonal and tetragonal sites in CaF2.

Analysis of angularly dependent ODNMR spectra of 151Eu3+ in LaF3.

The angular dependence and Zeeman splitting of optically detected nuclear magnetic resonance (ODNMR) spectra of the $^{7}\mathrm{F}_{0}$ ground state of $^{151}\mathrm{Eu}^{3+}$ in ${\mathrm{LaF}}_{3}$ have been measured in optical-rf double resonance experiments. Splitting of the degeneracy-left ODNMR spectrum is attributed to magnetically inequivalent ${\mathrm{Eu}}^{3+}$ sites. In analysis of the magnetic-field angle dependence of the spectra with an effective-operator Hamiltonian, nuclear quadrupole and magnetic interaction parameters as well as the orientation of the principal axes are determined. None of the principal axes coincides with the crystallographic axes. But the directions of the magnetic interaction tensors for different ${\mathrm{Eu}}^{3+}$ sites relate to each other according to a ${\mathit{C}}_{2}$ symmetry. \textcopyright{} 1996 The American Physical Society.

Laser spectroscopy and optical pumping in superfluid helium

In this paper, our recent works on the alkali atoms in superfluid helium (HeII) are reported. At first we mention the laser-sputtering method for implantation, which is simple but is very efficient to produce various kinds of neutral atoms and molecules in Hell. Secondly, we report on the laser spectroscopy of alkali atoms in Hell. Optical excitation and emission spectra are found to be explained by a spherical atomic bubble model. The emission spectra corresponding to the D 2 lines indicate the existence of quadrupole oscillations of the bubble shape. Optical pumping by a circularly polarized laser beam is found to produce perfect polarization, for both electron and nuclear spins. Using the rf-optical double resonance techniques, the magnetic and hyperfine resonances are observed. The quenching of the D line fluorescence by surrounding helium is also discussed.

A strongly driven two-level transition in a solid state: Small inhomogeneous broadening

The non-linear behavior of a two-level transition driven by a strong field plays an important role in the solid state laser spectroscopy, where the transitions are normally inhomogeneously broadened. In this paper, we study phenomena associated with the lesser-known situation in the solid state where the transition between two levels has little inhomogeneous broadening. The two-level transition studied involves hyperfine levels of nitrogen-vacancy color centers in diamond and is detected by an optical-RF double resonance technique. Many interesting effects will be described, including dynamic Stark splitting, Autler-Townes splitting, gain without inversion and multiphoton transitions.

Laser spectroscopy and optical pumping of alkali atoms in superfluid helium

In this paper, our recent works on the alkali atoms in superfluid helim (HeII) are reported. At first we mentions the laser-sputtering method for implantation, which is simple but is very efficient to produce various kinds of neutral atoms and molecules in HeII. Secondly, we report on the laser spectroscopy of alkali atoms in HeII. Optical excitation and emission spectra are found to be roughly explained by a spherical atomic bubble model, but the spectra corresponding to the D2 lines indicate the quadrupole oscillation of the bubble shape. Optical pumping by a circularly polarized laser beam is found to produce perfect polarization, for both electron and nuclear spins. Using the rf-optical double resonance techniques, the magnetic and hyperfine resonances are observed. It is discussed also about the phenomena which have observed in the experiments done so far but have not been fully explained.

Sublevel spectroscopy of alkali atoms in superfluid helium

We report the results of optical pumping and optical detection of magnetic resonance of alkali atoms (Cs and Rb) in superfluid helium. The magnetic resonances between the ground-state Zeeman sublevels and hyperfine levels are observed through monitoring theD1 fluorescence by means of the optical-rf double resonance technique. Although the ground stateg values in superfluid helium are the same as in vacuum within the experimental error, the hyperfine constant of the ground state of the Cs atom in superfluid helium is found to be slightly larger than in vacuum. Coherent transient spectroscopy is also performed.

Long electronic spin relaxation times of Cs atoms in solid 4He.

We report on optical pumping of Cs atoms implanted in a matrix of solid ${}^{4}$He at 1.6 K. Longitudinal spin relaxation times ${T}_{l}$ of 1--2 s have been measured using the ``relaxation in the dark'' method for magnetic holding fields in the range 0.01--1 G, for which no significant field dependence was found. Zero-field level-crossing resonances in longitudinal and transverse fields (ground-state Hanle effect) and conventional optical-rf double resonance of Cs atoms in solid ${}^{4}$He have been detected.

Zeeman quantum beat in nuclear quadrupole resonance probed by Raman heterodyne spectroscopy

The Zeeman quantum beat in nuclear quadrupole resonance of the diamond nitrogen-vacancy centre has been observed using Raman heterodyne spectroscopy — a coherent optical-RF double resonance technique. In the experiment, a magnetic field was applied and set corresponding to the level anticrossing regime, where the electron and nuclear spin states are strongly mixed and therefore the nuclear spin transitions are greatly enhanced. The 6380 Å 3A ↔3E zero-phonon transition was driven by a single mode CW laser while the mI = 0 ↔ ± 1 (mS = 0) magnetic transitions in the 3A ground state were excited by an RF pulse. Beat modulation was observed to appear as superimposed on the total RF emission signal detected by a photodiode. The beat frequency was found to be in excellent agreement with the Zeeman splitting of the mI = ± 1 (mS = 0) levels.

The fine and magnetic hyperfine structure of 87SrF in its X 2Σ+ state

A molecular beam rf–optical double resonance experiment was performed on 87SrF in its naturally occurring abundance ratio. The natural occurring abundances of the strontium isotopes are 86Sr (9.8%), 87Sr(7.02%) and 88Sr (82.5%). Numerous magnetic dipole allowed transitions between ρ-doublets in the X 2Σ+ state were measured to an accuracy of 3 kHz. The observed spectra were analyzed in terms of an effective Hamiltonian which includes the magnetic hyperfine and electric quadrupole interactions arising from the 87 Sr (I=9/2) and 19F (I=1/2) nuclei. The extracted spectroscopic hyperfine parameters were interpreted in terms of a simple molecular orbital picture for the electronic nature of the X 2Σ+ state. A comparison is made to previous results for the more abundant 86SrF and 88SrF isotopic forms.

Electronic Zeeman, hyperfine and superhyperfine interaction in CaF 2:HO 3+

A Ho 3+ centre in CaF 2 (B centre) [1] has been investigated. Contrary to previous assignment the centre has been established to have C 3v symmetry. Electronic Zeeman measurements give g z.sfnc; = 10 for the lowest crystal field doublet in the ground 5I 8 manifold. Electronic transitions show an eight line hyperfine pattern for a nuclear spin I = 7/2 of Ho 3+. MW-optical and RF-optical double resonance techniques have been used to study the hyperfine interaction and the super-hyperfine interaction in the ground state. Splitting of the super-hyperfine lines show that there is considerable distortion of the lattice near the RE 3+ ion.

Fine and magnetic hyperfine structure in the A 2Π and X 2∑+ states of yttrium monoxide

A molecular beam optical and rf–optical double resonance spectroscopic study of numerous vibrational components in the A2Π3/2–X2∑+ subband of gas phase YO has been performed. The fine and magnetic hyperfine parameters for v=0–4 of the X2∑+ state have been determined. The observed strong vibrational dependence of the spin–rotation parameter γ(X2∑+) is proposed to arise from a perturbation from two as yet unobserved low-lying 2Π states coming from a three open-shell configuration. The magnetic hyperfine parameters for the X2∑+ state can be interpreted in terms of a single unpaired electron model. An estimate for the A2Π excited state dipolar parameter has been established.