Remarkable enhancement of up-conversion luminescence by attenuated total reflectance structure

Up-conversion luminescence (UCL) enhancement of rare earth doped nanoparticles is particularly important and urgently required for biomedical and solar energy conversion applications. In this paper, a method of utilizing Kretschmann attenuated total reflectance (ATR) structure to enhance the UCL of NaYF4: Yb3+, Er3+ nanoparticles is reported, where the enhancement is attributed to surface plasmon waves (SPW) and guided waves. The UCL intensity of up-conversion nanoparticles (UCNPs) under first-order guided wave (TM1) mode is 200 times higher than direct excitation. We also studied the spectra of UCL at different detection angles of the ATR structure and found that the UCL here performs an interesting phenomenon that the reflection upconverted light spectra vary from red to green with the detection angle of the ATR system.