Photoluminescence study of Nd:YVO4 under high pressure

Pressure-induced changes of the fluorescence spectra of Nd:YVO4 crystals have been studied up to 10.88 GPa using a diamond anvil cell at ambient temperature. The changes of spectra indicate that pressure has remarkably influenced both the fluorescence intensity and the energy levels of Nd:YVO4 crystals. With pressure increasing up to 7.45 GPa, the intensity of the spectra decreases and the peak positions shift red gradually. For pressure above 7.5 GPa, the fluorescence intensity decreases quickly and the shift rates of the peaks is slowed down. This suggests that 7.5 GPa is a critical point of the pressure at which the crystal may have a pressure-induced phase transition and the crystal-field changes. The new characters of the fluorescence spectra remain stable as the pressure is released to ambient pressure.