An EPR study of Er<Superscript>3+</Superscript> impurities in RbTiOPO<Subscript>4</Subscript> single crystals

An electron paramagnetic resonance (EPR) study of Er<Superscript>3+ </Superscript> ions in single crystals of RbTiOPO<Subscript>4</Subscript> (RTP) is presented. The EPR spectra show the existence of six different Er<Superscript>3+</Superscript> centres. The g-matrix has been determined for these centres from the analysis of the angular dependences of the spectrum in three planes of the crystal. The study supports that erbium can enter the Rb<Superscript>+</Superscript> and Ti<Superscript>4+</Superscript> low-symmetry sites of RTP. This conclusion differs from those for KTP:Er<Superscript>3+</Superscript> and RTP codoped with Nb and Er. The different occupancies found for Er in these various crystals is suggested to be due to the differences in Er concentration. Copyright EDP Sciences/Società Italiana di Fisica/Springer-Verlag 2007