Control and enhancement of upconversion luminescence of NaYF4:Yb,Er nanoparticles with multiplet independent resonance modes in multiplexed metal gratings

Abstract

Resonant control of light–matter interactions is implemented usually by applying photonic resonance modes at either excitation or emission wavelengths, instead of both simultaneously, due to intrinsic limitations of conventional resonators. While, multiplet resonance modes in multiplexed gratings can be independently adjusted to control multi–frequency optical interaction processes in matters. In this work, we use multiplexed metal gratings to resonantly control and enhance upconversion luminescence (UCL) of NaYF4:Yb,Er nanoparticles by designing their doublet plasmon resonance modes locating at both the green– and red–UCL emission wavelengths, or both the excitation and one of the emission wavelengths, of the nanomaterial to improve the excitation/emission efficiencies. Experimental results show that, when the doublet plasmon resonance modes match both the excitation and green– or red–UCL emission wavelengths, the UCL enhancements can be further improved, accompanied with a large modification of the green– to red–UCL intensity ratios. The mechanisms are investigated by analyzing the internal transition processes based on measurements of dependences of the UCL emissions on excitation power and their lifetimes. The principles and resonance structures can be applied in a broad range of optical phenomena on light–matter interactions in which photons of multiple frequencies are involved.