Посилання:Spectroscopy of atomic and molecular defects in solid ⁴He using optical, microwave, radio frequency, magnetic and electric fields (Review Article) / P. Moroshkin, A. Hofer, S. Ulzega, A. Weis // Физика низких температур. — 2006. — Т. 32, № 11. — С. 1297–1319. — Бібліогр.: 82 назв. — англ.
Підтримка:The research work presented above is the fruit of
more than a decade of experimental and theoretical
efforts carried out by a number of undergraduate students,
Ph. D. students, and postdocs, and with the invaluable
support of mechanical and electronics technicians
and engineers. All their individual contributions
are acknowledged. The doctoral thesis works that
have emerged from this line of research were presented
by Markus Arndt [79] and Stephen Lang [80] at the
Ludwig-Maximilians Universitt in Munich, by Taro
Eichler [81] at the Friedrich-Wilhelms-Universitt in
Bonn and more recently by Daniel Nettels [82],
Reinhard M ller-Siebert [20] and Simone Ulzega [66]
at the University of Fribourg. One of us (A.W.) acknowledges
his colleague and friend Sergei Kanorsky
who submitted the original EDM proposal to the
Max-Planck-Institute for Quantum Optics and with
whom he initiated the first heroic steps of this research.
We thank Paul Knowles for his critical reading
of the manuscript.
The research was funded partly by the individual
host institutions and by the national funding agencies
in Germany (Deutsche Forschungsgemeinschaft,
DFG) and in Switzerland (Swiss National Science
Foundation, SNF). We particularly acknowledge the
support of SNF by the grants 21-59451.99,
20-67008.01, and 200020-103864.
A little more than a decade ago our team extended the field of defect spectroscopy in
cryocrystals to solid ⁴He matrices, in both their body-centered cubic (bcc) and hexagonally
close-packed (hcp) configurations. In this review paper we survey our pioneering activities in the
field and compare our results to those obtained in the related fields of doped superfluid helium and
doped helium nanodroplets, domains developed in parallel to our own efforts. We present experimental
details of the sample preparation and the different spectroscopic techniques. Experimental
results of purely optical spectroscopic studies in atoms, exciplexes, and dimers and their interpretation
in terms of the so-called bubble model will be discussed. A large part of the paper is devoted
to optically detected magnetic resonance, ODMR, processes in alkali atoms. The quantum nature
of the helium matrix and the highly isotropic shape of the local trapping sites in the bcc phase
make solid helium crystals ideal matrices for high resolution spin physics experiments. We have investigated
the matrix effects on both Zeeman and hyperfine magnetic resonance transitions and
used ODMR to measure the forbidden electric tensor polarizability in the ground state of cesium.
Several unexpected changes of the optical and spin properties during the bcc—hcp phase transition
can be explained in terms of small bubble deformations.