Search Results - (Author, Cooperation:W. Ertmer)

2011-10-15

American Association for the Advancement of Science (AAAS)

0036-8075

1095-9203

Biology

Chemistry and Pharmacology

Computer Science

Medicine

Natural Sciences in General

Physics

2018-10-13

Institute of Physics (IOP)

1367-2630

Physics

1089-7623

AIP Digital Archive

Physics

Electrical Engineering, Measurement and Control Technology

We have devised an all-optical setup for the generation of two phase-locked laser fields with a frequency difference of 3 GHz using only standard optics and two acousto-optical frequency shifters, that are operated at 253 MHz in sixtupel pass. The spectral width of the beat frequency is measured to be 300 Hz (full width at half maximum) limited by the resolution bandwidth of the spectrum analyzer. We routinely obtain an overall efficiency of more than 15% and demonstrate that the frequency shifted light can be further amplified by injecting it into additional "slave" lasers. This setup provides a low-cost alternative over conventional methods to generate laser fields with difference frequencies in the GHz domain, as for example, used in laser spectroscopy, laser cooling and trapping, and coherent manipulation of atomic quantum states. © 2000 American Institute of Physics.

Electronic Resource

0030-4018

Elsevier Journal Backfiles on ScienceDirect 1907 - 2002

Physics

Electronic Resource

0030-4018

Elsevier Journal Backfiles on ScienceDirect 1907 - 2002

Physics

Electronic Resource

0375-9601

Elsevier Journal Backfiles on ScienceDirect 1907 - 2002

Physics

Electronic Resource

0375-9601

Elsevier Journal Backfiles on ScienceDirect 1907 - 2002

Physics

Electronic Resource

0370-2693

Elsevier Journal Backfiles on ScienceDirect 1907 - 2002

Physics

Electronic Resource

1434-601X

Springer Online Journal Archives 1860-2000

Physics

Abstract The hyperfine structure (hfs) of the metastable atomic states 3d64s6 D 1/2, 3/2, 5/2, 7/2, 9/2 of55Mn was measured using theABMR- LIRF method (atomicbeammagneticresonance, detected bylaserinducedresonancefluorescence). The hfs constantsA andB, corrected for second order hfs perturbations, could be derived from these measurements. The theoretical interpretation of these correctedA- andB-factors was performed in the intermediate coupling scheme taking into account the configurations 3d 54s 2, 3d 64s and 3d 7. Examining the influence of the composition of the eigenvectors on the hfs parameters $$\left\langle {r^{ - 3} } \right\rangle ^{k_s k_l } $$ it was found, that for the configuration 3d 64s the two-body magnetic interaction should be considered in the calculation of the eigenvectors. Investigating second order electrostatic configuration interactions and relativistic effects and using calculated relativistic correction factors we obtained for the nuclear quadrupole moment of the nucleus55Mn a value ofQ=0.33(1) barn, which is not perturbed by a shielding or antishielding Sternheimer factor. The following hfs constants have been obtained: $$\begin{gathered} A\left( {{1 \mathord{\left/ {\vphantom {1 2}} \right. \kern-\nulldelimiterspace} 2}} \right) = 882.056\left( {12} \right)MHz \hfill \\ A\left( {{3 \mathord{\left/ {\vphantom {3 2}} \right. \kern-\nulldelimiterspace} 2}} \right) = 469.391\left( 7 \right)MHzB\left( {{3 \mathord{\left/ {\vphantom {3 2}} \right. \kern-\nulldelimiterspace} 2}} \right) = - 65.091\left( {50} \right)MHz \hfill \\ A\left( {{5 \mathord{\left/ {\vphantom {5 2}} \right. \kern-\nulldelimiterspace} 2}} \right) = 436.715\left( 3 \right)MHzB\left( {{5 \mathord{\left/ {\vphantom {5 2}} \right. \kern-\nulldelimiterspace} 2}} \right) = - 46.769\left( {30} \right)MHz \hfill \\ A\left( {{7 \mathord{\left/ {\vphantom {7 2}} \right. \kern-\nulldelimiterspace} 2}} \right) = 458.930\left( 3 \right)MHzB\left( {{7 \mathord{\left/ {\vphantom {7 2}} \right. \kern-\nulldelimiterspace} 2}} \right) = 21.701\left( {40} \right)MHz \hfill \\ A\left( {{9 \mathord{\left/ {\vphantom {9 2}} \right. \kern-\nulldelimiterspace} 2}} \right) = 510.308\left( 8 \right)MHzB\left( {{9 \mathord{\left/ {\vphantom {9 2}} \right. \kern-\nulldelimiterspace} 2}} \right) = 132.200\left( {120} \right)MHz \hfill \\ \end{gathered} $$

Electronic Resource

1434-601X

Springer Online Journal Archives 1860-2000

Physics

Abstract In our systematic investigations on the hyperfine structure (hfs) of high lying metastable states in 3d-shell atoms we have found evidence for an extraordinary strong far configuration mixing effect on off-diagonal matrix elements between configurations. Using theABMR-LIRF method the hfs of (3d 2 4s 2)3 P 47Ti, (3d 3 4s 2)4 P 51V (3d 5 4s 2)4 G 55Mn and (3d 6 4s 2)3 H 57Fe has been measured. Values found for the effective radial parameters $$a^{k_s k_l } $$ of the magnetic dipole interaction disagreed up to 300% with those known from hfs measurements of lower lying multiplets of the same configuration, even when intermediate coupling and electrostatically correlated second order hfs effects within each of the configurations are taken into account. We suggest that the main part of these discrepancies can be explained, if two-body core polarization is considered, which screens the ordinary one-body core polarization parametera 3d 10 . Preliminary values for the corresponding parameters are given.

Electronic Resource

1434-601X

Springer Online Journal Archives 1860-2000

Physics

Abstract The hyperfine structure of the metastable atomic states (3d 44s 2)5 D 1,2,3,4 of53Cr has been measured using theABMR-LIRF method (atomic beam magnetic resonance detected by laser induced resonance fluorescence). The dipole coupling constantsA and the quadrupole coupling constantsB are found to beA(5 D 1)=−17.624(2) MHzB(5 D 1)=−21.847(5) MHzA(5 D 2)=−25.113(2) MHzB(5 D 2)=−13.485(5) MHzA(5 D 3)=−35.683(2) MHzB(5 D 3)=15.565(5) MHzA(5 D 4)=−48.755(2) MHzB(5 D 4)=63.021(5) MHz. From these measured hfs constants the electric quadrupole moment for53Cr is calculated to beQ=−0.15 (5) barn. The 30% error takes into account the uncertainties due to configuration interaction effects (shielding and antishielding effects) and of deviations from pure SL-coupling for the states5 D 1,2,3,4.

Electronic Resource

1434-601X

Springer Online Journal Archives 1860-2000

Physics

Abstract A method of simultaneous parametrization of one- and two-body interactions in atomic hyperfine structure (HFS) of the configurations (3d+4s)N+2 is proposed. It is shown that the HFS of these configurations can be parametrized by the use of sixteen adjustable radial parameters for the magnetic dipole interaction and twelve radial parameters for the electric quadrupole interaction. From these one- and two-body parameters nuclear quadrupole moments can be evaluated which are almost free of Sternheimer corrections.

Electronic Resource

1432-1904

Springer Online Journal Archives 1860-2000

Biology

Chemistry and Pharmacology

Natural Sciences in General

Electronic Resource

1432-0649

32.80.-t ; 42.50.+q ; 07.60.Ly

Springer Online Journal Archives 1860-2000

Physics

Abstract In this paper it will be shown that an atom interferometer, based on the coherent splitting of the atomic wavefunction by four travelling waves (Ramsey interferometer), may be explained by a purely mechanical interpretation. As our first application of this Ramsey interferometer we have measured the phase shifts respectively optical length changes in a magnesium atomic beam caused by the acceleration of the partial atomic wave in one arm of the interferometer. This acceleration was achieved by the dipole force exerted by an off-resonant crossing laser beam which interacted with the ground state part of the wavefunction only. Further applications of this interferometer and improvements due to laser cooling will be discussed.

Electronic Resource

1432-0649

32.80 ; 35.10.-d ; 42.60.-v

Springer Online Journal Archives 1860-2000

Physics

Abstract We measured the isotope shift of the MgI intercombination line 3s3p 3 P 1-3s 2 1 S 0 (λ=457 nm) for the three stable isotopes 24Mg, 25Mg and 26Mg. The measurement was performed by optical Ramsey spectroscopy (respectively saturation spectroscopy for 25Mg) on a magnesium atomic beam. The rf precision of the measurement was achieved by using optical sideband techniques for the stabilization and tuning of a dye laser relative to an ultrastable cavity.

Electronic Resource

1432-0649

07.65.—b ; 32.80.Pj ; 42.50.+j

Springer Online Journal Archives 1860-2000

Physics

Abstract High-resolution spectroscopic measurements on the 457 nm Mg intercombination line are reported. Studies have been performed both on atoms contained in a magneto-optical trap and on atoms in a thermal beam. We present a detailed analysis of various factors influencing resolution and accuracy for both setups, including direct comparisons. With the trapped cold atoms, a stability of 8.7 × 10−13 within 20 s has been achieved together with an accuracy of 2 × 10−15. The direct comparison shows the limited stability of the thermal beam apparatus for integration times larger than 300 s. For shorter times, the thermal beam setup is at present more stable by a factor of three, mainly because of a better signal-to-noise ratio.

Electronic Resource

1432-0649

03.65.Bz ; 03.75.Be ; 32.80.Pj

Springer Online Journal Archives 1860-2000

Physics

Abstract Matter-wave interferences in a four-pulse version of a Ramsey-Bordé atom interferometer have been utilized to study phase shifts. A topological phase shift analogous to the scalar Aharonov-Bohm effect proposed for charged-particle interferences in the presence of a pulsed electrostatic potential has been investigated. The time-dependent potential has been generated by the interaction of a laser field with an induced atomic dipole without spatial variation along the interferometer arms. The atom interferometer has been run with laser-cooled magnesium atoms stored in a magneto-optical trap.

Electronic Resource

1432-0649

PACS: 06; 43

Springer Online Journal Archives 1860-2000

Physics

Such measurements require a special consideration of the electric setup which substantially affects the interpretation of the signals. In this paper we analyze these considerations and derive an algorithm that permits the correction of measured pressure transients.

Electronic Resource

1432-0649

PACS: 32.80.-t; 42.50.Vk

Springer Online Journal Archives 1860-2000

Physics

01 * (doughnut) modes for atomic beam manipulation. A slow atomic beam is guided over up to 0.3 m and focused down to 6.5 μm radius. The doughnut mode is used as a strong mesoscopic dipole potential with vibrational level spacings up to the photon recoil energy. Polarization gradient cooling in this system generates a bimodal momentum distribution with a narrow component momentum width of 4 ?k.

Electronic Resource

1432-0649

PACS: 03.75.Be; 32.80.Lg; 42.82.Cr

Springer Online Journal Archives 1860-2000

Physics

Abstract. We study different aspects of atom lithography with metastable neon atoms. Proximity printing of stencil masks is used to test suitable resists that are sensitive to the internal energy of the atoms, including dodecanethiols on gold and octadecyltrichlorosilanes grown on a SiO2 surface. As an example of patterning the atomic beam with laser light, we create parallel line structures on the surface with a periodicity of half the laser wavelength by locally de-exciting the atoms in a standing quenching wave.

Electronic Resource