共查询到20条相似文献,搜索用时 33 毫秒
1.
A. C. Wilson C. Ospelkaus A. P. VanDevender J. A. Mlynek K. R. Brown D. Leibfried D. J. Wineland 《Applied physics. B, Lasers and optics》2011,105(4):741-748
We present a solid-state laser system that generates 750 mW of continuous-wave, single-frequency output at 313 nm. Sum-frequency
generation with fiber lasers at 1550 and 1051 nm produces up to 2 W at 626 nm. This visible light is then converted to ultraviolet
by cavity-enhanced second-harmonic generation. The laser output can be tuned over a 495-GHz range, which includes the 9Be+ laser cooling and repumping transitions. This is the first report of a narrow-linewidth laser system with sufficient power
to perform fault-tolerant quantum-gate operations with trapped 9Be+ ions by use of stimulated Raman transitions. 相似文献
2.
We investigate the loading rate of Yb+ ions loaded through photoionization in a radiofrequency trap. The absolute or relative number of the loaded trapped ions
is measured by use of an electric resonance of the secular motion. This method is applicable even in the presence of anharmonicity.
In two-color photoionization, where the first-excitation laser drives the 1S0–1P1 transition in the Yb atom and the second one ionizes the atom from the 1P1 state, the loading rate is at its highest by the excitation of the ionization potential. A similar loading rate is observed
at the second-laser wavelength around 369.5 nm, which is the wavelength for the cooling transition of Yb+. We estimate the loading cross section to be 40(15) Mb for the two-color excitation of the ionization potential. The excitation
of the Yb atoms in the Rydberg states is detected by the enhancement of the loading rate. By irradiation with only the first-excitation
laser, Yb+ is produced at a rate three orders of magnitude smaller than that when the non-resonant two-photon absorption from the 1P1 state is the dominant process. We also measure the charge-exchange rate between Yb+ and Yb, and discuss its effect on isotope-selective photoionization loading. 相似文献
3.
We report laser cooling of trapped 171Yb+ ions. The ions are confined in a linear Paul trap. Temperatures below 1 K have been achieved, and evidence of a phase transition to a crystal-like state has been observed. The metastable 2
D
3/2 level is drained using a transition at 609.1 nm not previously used for this purpose. Laser cooling of 171Yb+ may be of importance to the development of new microwave frequency standards. 相似文献
4.
V. Sonnenschein I. D. Moore S. Raeder A. Hakimi A. Popov K. Wendt 《The European Physical Journal A - Hadrons and Nuclei》2012,48(4):52
An overview of preparatory work aiming at the identification of the low-lying 7.6 eV isomer in 229Th through a measurement of its hyperfine structure is presented. A 233U recoil gas cell has been developed and has undergone several iterations in order to improve the efficiency of extracting
a low-energy beam of 229Th+ ions. Spectroscopic studies on stable 232Th have been carried out to establish an efficient laser ionization scheme. The latter will be applied in connection with
the gas cell in order to improve the extraction efficiency by accessing the neutral atomic fraction. In addition to that of
the 229Th ground state, the hyperfine structure of the isomer can then be determined either by collinear laser spectroscopy on the
extracted and accelerated ions or by direct in-source/in-jet high-resolution Resonance Ionization Spectroscopy (RIS). The
first experiments using high-resolution RIS have been performed and isotope shifts of 228Th, 229Th and 230Th relative to 232Th were measured on an atomic 7s
2 → 7s7p ground-state transition at 380.42 nm. A template of the ground-state hyperfine structure of 229Th has been established for a 261.24 nm UV transition. This is an important step towards identification of the isomeric state. 相似文献
5.
The transition between the two Zeeman sublevels of 2S1/2 in a single trapped 40Ca+ ion is directly excited by a radio-frequency magnetic field. A coherence time of 29.4±2.5 ms is measured by Ramsey interferometry.
The ratio of the maximum Rabi frequency of the Zeeman transition (∼250 kHz) to the inverse of the coherence time is 7.3×103, which is considered to be a figure of merit for Zeeman states when they are used as a quantum bit. Several applications
of the Zeeman qubit to quantum information processing are also discussed. 相似文献
6.
We demonstrate a three-step laser stabilization scheme for excitation to nP and nF Rydberg states in 85Rb, with all three lasers stabilized using active feedback to independent Rb vapor cells. The setup allows stabilization to
the Rydberg states 36P3/2–70P3/2 and 33F7/2–90F7/2, with the only limiting factor being the available third step laser power. We study the scheme by monitoring the three laser
frequencies simultaneously against a self-referenced optical frequency comb. The third step laser, locked to the Rydberg transition,
displays an Allan deviation of 30 kHz over 1 second and <80 kHz over 1 hour. The scheme is very robust and affordable, and
it would be ideal for carrying out a range of quantum information experiments. 相似文献
7.
B. Hemmerling F. Gebert Y. Wan D. Nigg I. V. Sherstov P. O. Schmidt 《Applied physics. B, Lasers and optics》2011,104(3):583-590
We present a single solid-state laser system to cool, coherently manipulate and detect 25Mg+ ions. Coherent manipulation is accomplished by coupling two hyperfine ground state levels using a pair of far-detuned Raman
laser beams. Resonant light for Doppler cooling and detection is derived from the same laser source by means of an electro-optic
modulator, generating a sideband which is resonant with the atomic transition. We demonstrate ground-state cooling of one
of the vibrational modes of the ion in the trap using resolved-sideband cooling. The cooling performance is studied and discussed
by observing the temporal evolution of Raman-stimulated sideband transitions. The setup is a major simplification over existing
state-of-the-art systems, typically involving up to three separate laser sources. 相似文献
8.
We measured the absorption and luminescence spectra of Nd3+ ions in an inorganic solvent POCl3-BCl3. The spectra were analyzed in terms of the Judd-Ofelt theory. We calculated the Judd-Ofelt parameters, oscillator strengths,
spontaneous emission probabilities, luminescence quantum yield, and the stimulated emission cross section for the laser transition
4
F
3/2 → 4
I
11/2 of the neodymium ion in a POCl3-BCl3-Nd3+ solution. 相似文献
9.
With the advent of high-precision frequency combs that can bridge large frequency intervals, new possibilities have opened
up for the laser spectroscopy of atomic transitions. Here, it is shown that laser spectroscopic techniques can also be used
to determine the ground-state g factor of a bound electron. The proposal is based on a double-resonance experiment, where the spin state of a ground-state
electron is constantly being read out by laser excitation to the atomic L shell, while the spin flip transitions are being induced simultaneously by a resonant microwave field, leading to the detection
of the quantum jumps between the ground-state Zeeman sublevels. The magnetic moments of electrons in light hydrogen-like ions
could thus be measured with advanced laser technology. Corresponding theoretical predictions are also presented.
The text was submitted by the authors in English. 相似文献
10.
The luminescent properties of Eu3+ and Eu2+ ions in sodium pyrophosphate, Na4P2O7, have been studied. The excitation spectrum of the Eu3+ emission in Na4P2O7 consists of several sets of bands in the range 280–535 nm due to 4f–4f transitions of Eu3+ ions and a broad band with a maximum at about 240 nm interpreted to be due to a charge transfer (CT) transition from oxygen
2p states to empty states of the Eu3+ 4f6-configuration. Although the CT band energy is large enough, the quantum efficiency (η) of the Eu3+ emission in Na4P2O7 under CT excitation was estimated to be very low (η ≤ 0.01). In terms of a configurational coordinate model, this fact is
interpreted as a result of the high efficiency of a radiationless relaxation from the CT state to the 7F0 ground state of Eu3+ ions occupying sodium sites in Na4P2O7. A strong reducing agent is required in order to stabilize Eu2+ ions in Na4P2O7 during the synthesis. Several nonequivalent Eu2+ luminescence centers in Na4P2O7 were found. 相似文献
11.
F. Schmidt-Kaler J. Eschner G. Morigi C.F. Roos D. Leibfried A. Mundt R. Blatt 《Applied physics. B, Lasers and optics》2001,73(8):807-814
A novel method of ground-state laser cooling of trapped atoms utilizes the absorption profile of a three- (or multi-) level
system that is tailored by a quantum interference. With cooling rates comparable to conventional sideband cooling, lower final
temperatures may be achieved. The method was experimentally implemented to cool a single Ca+ ion to its vibrational ground state. Since a broad band of vibrational frequencies can be cooled simultaneously, the technique
will be particularly useful for the cooling of larger ion strings, thereby being of great practical importance for initializing
a quantum register based on trapped ions. We also discuss its application to different level schemes and for ground-state
cooling of neutral atoms trapped by a far-detuned standing wave laser field.
Received: 10 July 2001 / Published online: 23 November 2001 相似文献
12.
N. Akerman Y. Glickman S. Kotler A. Keselman R. Ozeri 《Applied physics. B, Lasers and optics》2012,107(4):1167-1174
We report on the construction and characterization of an apparatus for quantum information experiments using 88Sr+ ions. A miniature linear radio-frequency (rf) Paul trap was designed and built. Trap frequencies above 1 MHz in all directions are obtained with 50 V on the trap end-caps and less than 1 W of rf power. We encode a quantum bit (qubit) in the two spin states of the S 1/2 electronic ground-state of the ion. We constructed all the necessary laser sources for laser cooling and full coherent manipulation of the ions’ external and internal states. Oscillating magnetic fields are used for coherent spin rotations. High-fidelity readout as well as a coherence time of 2.5 ms are demonstrated. Following resolved sideband cooling the average axial vibrational quanta of a single trapped ion is $\bar{n}=0.05$ and a heating rate of $\dot{\bar{n}}=0.016~\mathrm{ms}^{-1}$ is measured. 相似文献
13.
Luminescence regularities have been studied in new erbium/ytterbium materials based on glasses and glass ceramics of a magnesium-aluminosilicate
system containing nanoscale erbium/ytterbium zirconate titanate crystals with the pyrochlore structure. Lifetimes of Yb3+ and Er3+ ions in the 2 F5/2 state and in the 4I11/2 and 4I13/2 states, respectively, and the efficiency of Yb3+ → Er3+ energy transfer have been evaluated. The identified spectral-luminescent characteristics of the studied glasses and glass
ceramics co-doped with erbium and ytterbium ions show that these materials are promising media for producing laser generation
in the spectral range around 1.5 μm. 相似文献
14.
Data on the cross sections for single-electron charge exchange and excitation in collisions of He+ ions with C5+, N6+, and O7+ ions in the He+ ion energy range of 0.2–3.0 MeV are obtained for the first time. The cross sections for the single-electron charge transfer
into the singlet and triplet 1snl states of C4+, N5+, and O6+ (2≤n≤5) ions and for the 1s → 2p
0, ±1 electronic excitation of He+(1s) ions are calculated. The calculations were performed by solving close-coupling equations on the basis of ten two-electron
quasi-molecular states. 相似文献
15.
O. N. Prudnikov A. V. Taichenachev V. I. Yudin E. M. Rasel 《Bulletin of the Russian Academy of Sciences: Physics》2017,81(12):1420-1428
The possible deep laser cooling of 24Mg atoms in a deep optical lattice in the presence of an additional pumping field resonant to the narrow 3s3s1S0 → 3s3p3P1 (λ = 457 nm) optical transition is studied. Two quantum models of the laser cooling of atoms in the optical trap are compared. One is based on the direct numerical solution to the kinetic quantum equation for an atomic density matrix; it considers both optical pumping and quantum recoil effects during interaction between the atoms and field photons. The second, simplified model is based on decomposing the states of the atoms over the levels of vibration in the optical trap and analyzing the evolution of these states. The comparison allows derivation of optical field parameters (pumping field intensity and detuning) that ensure cooling of the atoms to minimal energies. The conditions for fast laser cooling in an optical trap are found. 相似文献
16.
X. G. Wu M. J. Wan C. Q. Song T. Gao 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2010,60(2):263-267
Electronic structure and spectroscopic properties B
e, ωe, ωe
x
e, αe, T
e
of ground state and the low-lying excited states of HF+ and HF- molecular ions were
investigated within scalar relativistic multireference configuration
interaction with single and double excitations framework using the GAMESS-US
program package. All potential energy curves (PECs) were calculated using
the relativistic complete active space self-consistent field/spin-orbit
multi-configuration quasi-degenerate perturbation theory (CASSCF/SO-MCQDPT).
The curves are all fitted to the analytical potential energy function
(APEF), from which accurate spectroscopic constants are derived. The
spin-orbit splitting was also been studied, the split value of X2P^{2}{\rm \Pi} state of HF+ is determined to be 288.38 cm-1. The calculated properties are in good agreement with the available experimental value.
Spectroscopic constants of the ground states of HF- that have never
been observed in experiment are obtained. These curves provide an
interpretation of the known experimental observations on this system and
suggest a number of further experiments which possible provide a critical
test of this data. 相似文献
17.
Vinod Kumar Pragya Das R.P. Singh S. Muralithar R.K. Bhowmik 《The European Physical Journal A - Hadrons and Nuclei》2003,17(2):153-157
The fusion evaporation reaction 122Sn(14N, 4n)132La was used to populate the high-spin states of 132La at the beam energy of 60 MeV. A new band consisting of mostly E2 transitions has been discovered. This band has the interesting links to the ground state 2- and the isomeric state 6-. A new transition of energy 351 keV connecting the low-spin states of the positive-parity band based on the πh
11/2 ⊗ νh
11/2 particle configuration, has been found. This has played a very important role in resolving the existing ambiguities and inconsistencies
in the spin assignment of the band head.
Received: 12 August 2002 / Accepted: 18 March 2003 / Published online: 7 May 2003 相似文献
18.
A.B. Mundt A. Kreuter C. Russo C. Becher D. Leibfried J. Eschner F. Schmidt-Kaler R. Blatt 《Applied physics. B, Lasers and optics》2003,76(2):117-124
We demonstrate coherent coupling of the quadrupole S1/2D5/2 optical transition of a single trapped 40Ca+ ion to the standing wave field of a high-finesse cavity. The dependence of the coupling on temporal dynamics and spatial
variations of the intracavity field is investigated in detail. By precisely controlling the position of the ion in the cavity
standing wave field and by selectively exciting vibrational state-changing transitions the ion’s quantized vibration in the
trap is deterministically coupled to the cavity mode. We confirm coherent interaction of ion and cavity field by exciting
Rabi oscillations with short resonant laser pulses injected into the cavity, which is frequency-stabilized to the atomic transition.
Received: 23 August 2002 / Published online: 8 January 2003
RID="*"
ID="*"Corresponding author. E-mail: christoph.becher@uibk.ac.at
RID="**"
ID="**"Present address: Time and Frequency Division, National Institute of Standards and Technology, Boulder, CO 80305, USA 相似文献
19.
K. Blagoev R. Roussev A. Morozov K. Iskra L. Windholz 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2001,13(2):159-163
Radiative lifetimes of 7d, 8d 1
D
2 excited states of Hg I are measured using pulsed two-photon excitation from the ground [Xe]5d
106s
2
1
S
0 mercury state, detecting the decay of the laser-induced fluorescence. The results are compared with theoretical values, obtained
by means of a Hartree-Fock single configuration method, taking into account electron configuration interaction. The radiative
lifetime value dependence on the effective principal quantum number for the nd 1
D
2 series is analyzed and compared with the quantum defect dependence.
Received 25 February 2000 and Received in final form 26 July 2000 相似文献
20.
A new analytical potential energy function for diatomic molecular ion XY+ is proposed based on the energy consistent method (ECM). The Coulomb potential included in the new ionic potential contains
multipole corrections, converges quickly and is variationally, changeable. The new potential and the ECM are applied to variationally
studying the potential energies of eight electronic states of several diatomic molecular ions: the A2π state of CO+, the X2∑g+ state of Li2+, the X2∑g+ state of He2+, the 12∏u state of Na2+, the A2∏u state of N2+, the X1∑+ state of KrH+, the X2∑+ state of SiO+ and the A2π state of SO+ ion. The present results agree excellently with the experiment-based Rydberg-Klein-Rees (RKR) potentials, and are superior
to the commonly used Huxley-Murrell-Sorbie (HMS) analytical potentials, and are better in some cases than some quantum mechanicalab initio potentials in the ionic asymptotic and dissociation regions. 相似文献