A Novel Approach from Infrared to Ultraviolet Emission Enhancement in Yb3+, Er3+:CaF2 Nanofilms

Under 978 nm excitation, we explored the infrared-to-ultraviolet upconversion properties in the nanofilms with the nanoparticles of Yb 3+ , Er 3+ codoped calcium fluoride (CaF 2 :Yb 3+ , Er 3+ ). The strong enhancement of ultraviolet emission was observed. The result is attributed to the optical performance characteristics of the nanostructure materials. Furthermore, a novel upconversion approach explains well the UV-enhanced emission.