共查询到20条相似文献,搜索用时 15 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 here developed and evaluated a laser frequency control system which synchronizes the laser frequency to the resonance of target Ca + isotope ion whose having more than 8 GHz of isotope shift based on the Fringe Offset Lock method for simple operation of ICPMS-ILECS (Inductively Coupled Plasma Mass Spectrometry - Ion trap Laser Cooling Spectroscopy) The system fulfilled the minimum requirements of four slave lasers stability for Doppler cooling of Ca + ions. A performance of the system was evaluated by cooling 40Ca + ions with the stabilized slave lasers. All the stable even Ca + isotope ions were trapped and their fluorescence was observed by switching laser frequencies using the system. An odd calcium isotope 43Ca +cooling was also succeeded by the control system. 相似文献
3.
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
4.
A. V. Artamonov V. P. Astakhov V. V. Karpov 《Journal of Surface Investigation: X-ray, Synchrotron and Neutron Techniques》2016,10(1):43-47
The results of the second-photon-stimulated annealing of beryllium-implanted InAs layers are presented. The hole and electron concentrations and the activation energy of second-photon-stimulated annealing are calculated for the characteristic temperature regions using thermopower voltage values measured for the implanted layer. The possible mechanisms of the annealing of radiation-induced defects and the activation of beryllium atoms are discussed. 相似文献
5.
A. D. Pogrebnyak S. N. Bratushka L. V. Malikov N. Levintant N. K. Erdybaeva S. V. Plotnikov B. P. Gritsenko 《Technical Physics》2009,54(5):667-673
The surface layer of an equiatomic TiNi alloy, which exhibits the shape memory effect in the martensitic state, is modified
with high-dose implantation of 65-keV N+ ions (the implantation dose is varied from 1017 to 1018 ions/cm2). TiNi samples are implanted by N+, Ni+-N+, and Mo+-W+ ions at a dose of 1017–1018 cm−2 and studied by Rutherford backscattering, scanning electron microscopy, energy dispersive spectroscopy, X-ray diffraction
(glancing geometry), and by measuring the nanohardness and the elastic modulus. A Ni+ concentration peak is detected between two maxima in the depth profile of the N+ ion concentration. X-ray diffraction (glancing geometry) of TiNi samples implanted by Ni+ and N+ ions shows the formation of the TiNi (B2), TiN, and Ni3N phases. In the initial state, the elastic modulus of the samples is E = 56 GPa at a hardness of H = 2.13 ± 0.30 GPa (at a depth of 150 nm). After double implantation by Ni+-N+ and W+-Mo+ ions, the hardness of the TiNi samples is ∼2.78 ± 0.95 GPa at a depth of 150 nm and 4.95 ± 2.25 GPa at a depth of 50 nm;
the elastic modulus is 59 GPa. Annealing of the samples at 550°C leads to an increase in the hardness to 4.44 ± 1.45 GPa and
a sharp increase in the elastic modulus to 236 ± 39 GPa. A correlation between the elemental composition, microstructure,
shape memory effect, and mechanical properties of the near-surface layer in TiNi is found. 相似文献
6.
M. Tacconi F. A. Gianturco 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2008,46(3):443-451
The electronic structures of the manifold of potential energy surfaces generated in the lower energy range by the
interaction of the MgH+(X1Σ+) cationic molecule with Rb(2S) neutral atom are obtained over a broad range of
Jacobi coordinates from strongly correlated ab initio calculations which use a Multireference (MR) wavefunction within
a Complete Active Space (CAS) approach. The relative features of the lowest five surfaces are analyzed in terms of
possible collisional outcomes when employed to model
the ultracold dynamics of ionic molecular partners. 相似文献
7.
L. S. Danelyan V. V. Zatekin S. N. Korshunov V. S. Kulikauskas A. N. Mansurova 《Journal of Surface Investigation: X-ray, Synchrotron and Neutron Techniques》2011,5(2):269-271
V-5Ga-6Cr and V-5Ga-0.05Ce vanadium alloys irradiated by Ar+ and N+ ions with energies of 20 keV have been investigated. Irradiation by Ar+ and N+ ions leads to strengthening of the surface layers of samples. Their thicknesses exceed the projectile ranges of these ions
(16.4 and 32.8 nm, respectively) in vanadium by more than two orders of magnitude. The experimentally determined penetration
depth of argon ions is less that 70 nm. The sample side irradiated by Ar+ ions has a predominant orientation of crystallites in the (100) and (211) planes, while the unirradiated sample has a (110)
surface. The lattice parameter of the irradiated sample does not differ from that of the initial sample. Possible mechanisms
by which modified deep layers are formed during ion bombardment are discussed. 相似文献
8.
M. K. Pandey R. K. Dubey D. N. Tripathi 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2007,41(2):275-279
The Classical Trajectory Monte Carlo (CTMC) Method has
been used to calculate the differential, partial and total single electron
capture cross sections for the collision of H+/D+ with Ca and Mg
atoms in the energy range of 1–100 keV. The differential cross sections
at angles near the diffraction limit (<0.1○) in both systems
show a forward peak followed by an asymptotic fall at higher angles. Total
and partial capture cross sections are found to be in good agreement with
the experimental observations. Oscillations in the partial capture cross sections have been explained due to the swapping
of the field electron.
Isotope effect in the electron transfer is reported to be negligible. 相似文献
9.
Cadmium ions trapped in a linear Paul trap have been laser cooled by use of a microwave transition as a repumping process. A 15.2-GHz microwave transition between a ground-state hyperfine splitting is used for repumping, while an all-solid-state laser with the wavelength of 214 nm drives the cooling transition between the 2
S
1/2 and 2
P
3/2 states. A phase transition from the cloud state to the crystal state of trapped ions has been observed both in fluorescence spectra and in images of an ion string. Cadmium ions have potential of application for quantum information processing where the ground-state microwave transition is used for both a repumping process and manipulation of quantum states of trapped ions. PACS 32.80.Pj 相似文献
10.
M. A. Gubin A. N. Kireev Yu. V. Korostelin A. I. Landman Yu. P. Podmarkov M. Yu. Filipchuk M. P. Frolov A. I. Shelkovnikov 《Bulletin of the Lebedev Physics Institute》2011,38(7):205-208
Continuous tuning of the lasing wavelength from 2350 to 3450 nm in the cw Cr2+:CdSe laser is demonstrated. It is shown that the laser efficiently operates at a wavelength of 3.28 μm, which is promising for the methane optical frequency standard. The single-frequency mode of the laser with a lasing linewidth
not exceeding 60 MHz is implemented in this spectral range. 相似文献
11.
The master laser of an injection-seeded laser for Doppler wind lidar is frequency stabilized to a FabryPerot (FP) cavity using Pound-Drever-Hall technique. The FP cavity is specially designed to gain high temperature stability with Zerodur cavity and spacer. A computer based controller is used to sample and process the error signal. After the master laser is locked, the relative frequency drift is±25 kHz in 1 s,and ±55 kHz in 1 h, which can satisfy the need of Doppler wind lidar. 相似文献
12.
Y. Hashimoto M. Kitaoka T. Yoshida S. Hasegawa 《Applied physics. B, Lasers and optics》2011,103(2):339-344
We report the observation of sympathetically cooled 43Ca+ (natural abundance 0.135%) in a linear ion trap utilizing simultaneously trapped isotope ions as coolant. We investigated
different possibilities of realizing efficient sympathetic cooling and observed the peaks of the hyperfine transitions of
43Ca+ under various experimental conditions. 相似文献
13.
S. Kumari L. K. Jha B. N. Roy 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2009,55(1):93-97
Electron impact double ionization cross-sections of Sc+ions have been
calculated in the binary encounter approximation (BEA). Accurate expression
of σΔE(cross-section for energy transfer ΔE) and
Hartree-Fock velocity distributions for the target electrons have been used
throughout the calculations. Direct double ionization from ejection of 3d
and 4s electrons has been investigated in the modified double binary
encounter model incorporating the focusing action of the target ion on the
incident electron. The identification of the 3p shell whose ionization
provides a major contribution to double ionization through
ionization-autoionization is an interesting aspect of the present
investigation. The theoretical results show satisfactory agreement with the
experimental observations. 相似文献
14.
The formation of Na+ and Cs+ ions on and their thermal desorption from the surface of a NaAu alloy film grown on metallic gold are studied. It is shown
that thermionic emission from insulator-coated metallic substrates is governed by a sequence of processes, such as diffusion
of Na and Cs adatoms into the film, ionization of these atoms at the insulator-metal interface, diffusion of the resulting
ions toward the surface, and desorption of the ions. The effect of weak electric fields on ion diffusion and desorption is
investigated. 相似文献
15.
J. Lecointre D. S. Belic S. Cherkani-Hassani P. Defrance 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2011,63(3):441-448
Absolute cross sections for electron impact dissociation of ND+ leading to the formation of D+ have been measured by applying the animated electron-ion beam method in the energy range from the reaction threshold up to
2.5 keV. The maximum inclusive cross section is observed to be (16.8 ± 0.8) × 10−17 cm2 at the electron energy of 65.1 eV. The appearance energy for the D+ production is measured to be (4.0 ± 0.5) eV. Collected data are analyzed in details by means of an original procedure in
order to determine separately the contributions of dissociative channels. A specific Monte Carlo modeling has been developed,
which is proven to reconstruct adequately the dissociative ionization cross section. The present energy thresholds provide
information about the ground and excited states of the molecular ion, as well as about the possible population of the vibrational
levels. The reaction D2(v) + N+ (or H2(v) + N+) is a probable source for that population and it constitutes the first step of the molecular activated processes, so the
corresponding chain of reactions has to be considered to study the chemistry of plasma sources. 相似文献
16.
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
17.
A. Merli F. Sauer L. Wöste A. Lindinger 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2007,42(2):217-220
We report on isotope selective three-photon ionization of
two isotopomers of KRb by applying evolution strategies. The
particularity of this experiment is based on the high resolution
phase and amplitude modulation of the fs-laser pulses provided by a
2 × 640 pixel pulse shaper. The optimization in a closed feedback
loop performed with spectrally broad pulses centered at 840 nm shows
high enhancements of one isotopomer at the expense of the other
isotopomer and vice versa. From the optimal laser field we aim to
gain details about the selective ionization sequence and the
wavepacket evolution on the involved vibrational states. 相似文献
18.
R.M. Godbole S.K. Rai S. Raychaudhuri 《The European Physical Journal C - Particles and Fields》2007,50(4):979-990
The electromagnetic radiation emitted by colliding beams is expected to play an important role at the next generation of high
energy e+e- linear colliders. Focussing on the simplest process, e+e-→μ+μ-, we show that, for suitable machine parameters and luminosity, radiative effects like initial state radiation (ISR) and beamstrahlung
can be used to search for resonant graviton modes of the Randall–Sundrum model in an efficient manner. 相似文献
19.
S. Kar Y. K. Ho 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2007,44(1):1-8
We have investigated the ground state and the doubly excited 1,3P○ resonance states of plasma-embedded Li+ ion. The plasma effect is taken care of by using a screened Coulomb potential obtained from the Debye model. A correlated
wave function has been used to represent the correlation effect between the charged particles. The ground state of Li+ in plasmas for different screening parameters has been estimated in the framework of Rayleigh-Ritz variational principle.
In addition, a total of 18 resonances (9 each for 1P○ and 3P○ states) below the n=2 Li+ thresholds has been estimated by calculating the density of states using the stabilization method. For each spin state, this
includes four members in the 2snp+ (2≤n ≤5) series, three members in the 2snp- (3≤n ≤5) series, and two members in the 2pnd (n=3, 4) series. The resonance energies and widths for various Debye parameters
ranging from infinity to a small value for these 1,3P○ resonance states along with the ground state energies of Li+ and the Li2+ (1S), Li2+ (2S) threshold energies are reported. Furthermore, the wavelengths for the photo-absorption of lithium ion from its ground
state to such 1P○ resonance states for different Debye lengths are also reported. 相似文献
20.
The effect of proton irradiation (E = 5 MeV, D = 2 · 1017 cm−2) on electro-physical properties of p-CdSiAs
2 crystals is studied. The irradiation resulted in semi-insulating CdSiAs
2 samples with the Fermi-level position in the proximity of Eg/2. The energy position of a “neutral” point is calculated for CdSiAs
2, and thermal stability of radiation defects is investigated.
__________
Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 8, pp. 12–15, August, 2007. 相似文献