Nuclear quadrupole optical hole-burning in stoichiometric EuVO4

This study of EuVO 4 is the first application of hole-burning techniques to the investigation of defect sites in a rare-earth compound. Laser excitation of the Eu 3+ absorption spectrum in the region of the 7 F 0 - 5 D 0 forbidden transition ( approximately=580 nm) reveals some 30 absorption lines. Each corresponds to a distinct crystallographic site in EuVO 4 , as there are no crystal-field splittings in a 0-0 transition. Hole-burning of several of these lines indicates a wide range of quadrupole splitting parameters P and eta , as would be expected for different crystallographic sites. More detailed study of two of these hole-burning spectra shows that, once the parameters P and eta are determined, Zeeman spectra of selected holes directly determine the orientation of the quadrupole tensor relative to the crystallographic axes. In such a simple crystal structure as EuVO 4 it is not at all obvious that there could be as many as 30 different type of defect site, and further studies will be needed to explain this.