Ultraviolet light and near-infrared femtosecond pulsed laser excited visible photoluminescence in nd⁰ ions-doped oxide glasses

Abstract

We have systematically investigated the photoluminescence properties of Ti ⁴⁺, Zr⁴⁺, Nb⁵⁺, Ta⁵⁺, Mo⁶⁺, W⁶⁺, i.e., nd⁰ ions-doped oxide glasses when they are subject to ultraviolet light and near-infrared femtosecond pulsed laser, in which the latter is associated with a multiphoton process. The photoluminescence excited by ultraviolet light is found to cover a wide spectral space ranging from blue to orange wavelength, depending on the species of nd⁰ ions. The photoluminescence spectral profiles excited by near-infrared femtosecond laser are well consistent with those excited by ultraviolet light as to Ti ⁴⁺, Nb⁵⁺ and Ta⁵⁺ ions-doped glasses, while spectral variance occurs in case of Zr⁴⁺, Mo⁶⁺ and W⁶⁺ ions-doped glasses. The proposal of the existence of nd⁰ energy levels can partially interpret the observed phenomena while a complex mechanism should be developed to clarify the divergence of photoluminescence.