Hydrostatic-pressure dependence of Raman-active optical phonons in Nd:Mg:LiNbO3

Abstract In this work, we report the frequency variation of Raman phonon modes of a doped Nd:Mg:LiNbO3 crystal under high hydrostatic pressure up to 6.5 GPa. Whereas most of the phonon modes are not affected by doping, showing the same pressure dependence of their frequency as for undoped LiNbO3, there are three exceptions: The A1(TO)2, the A1(TO)3 and the E(TO)4 phonons. These modes exhibit a considerably different pressure coefficient, which is mainly attributed to the influence of Mg ions occupying Nb-sites in the lithium niobate matrix.