Self-suspended rare-earth doped up-conversion luminescent waveguide:
propagating and directional radiation


Rare-earth(RE)-doped up-conversion(UC)-luminescent materials excited with near-infrared light have attracted enormous attention because of their unique emission characteristic and broad application. Enhancing the fluorescence intensity and guiding the emission direction are essential factors for achieving full control on fluorescence emission. Luminescent waveguide is an effective system for controlling the radiation direction and guiding the light transmission on the designed scale. Recently, the development on micro/nano materials with various configuration or morphology offers opportunity for studying the waveguide effect with micro or nano particles, for example, RE doped UC-luminescent waveguide.

Prof. Hongxing Xu from Wuhan University and Prof. Hairong Zheng from Shaanxi Normal University reported a self-suspended UC-luminescent waveguide by using a RE-doped crown-shaped microparticle to investigate the UC-luminescent propagation and directional emission. As shown in Figure 1, an amazing UC-luminescent pattern with controllable directional emission is observed under the excitation at 980 nm. In addition to the enhancement of fluorescence intensity, controlling the emission direction to improve detection efficiency has become a promising approach for obtaining luminescence emission with certain spatial distribution and higher brightness. Benefitting from the special morphology of the crown-like NaYF4:Yb3+/Er3+ microparticle, an air layer is formed between the waveguide and substrate, greatly reducing the energy-coupling loss and enhancing transmission efficiency. With this system, a controllable directional emission with attractive UC luminescent pattern is observed, and the spatial emission angle and intensity distribution are investigated in detail by applying Fourier imaging detection and numerical simulation. It is shown that the fluorescence total reflection mode is suited to the self-suspended UC luminescent waveguide. Moreover, analysis of Fourier imaging and simulation is useful to exploring the transmission and emission modes of the RE-doped nano/micro UC-luminescent waveguide. The work provides a new method of achieving controllable directional fluorescence emissions and obtaining improved detection efficiency by guiding the emission direction, which has potential applications in 3-dimensional displays, micro-optoelectronic devices and self-fluorescence micron lasers.

Figure 1 Schematic of the directional UC emission of crown-shaped waveguide
and its experimental and simulated UC luminescent patterns

About The Group

Prof. Hongxing Xu is a professor of physics in Wuhan University (WHU) and a member of Chinese Academy of Sciences. He received Ph.D. from Chalmers University of Technology, Sweden, in 2002, and then joined Lund University, Sweden, as an assistant professor until December 2004. From 2005 to 2014, he was a professor at Institute of Physics, Chinese Academy of Sciences. His research interest is plasmon photonics, nano optics, single-molecule spectroscopy and nano optical chips. He has made pioneering and systematic work in the field of single-molecule surface-enhanced Raman spectroscopy and plasmonics. Meanwhile, Prof. Xu is a specially invited guest professor of Shaanxi Normal University (SNNU), working with the research group of Laser Spectroscopy and Luminescent Dynamics. The group contains 6 staffs including the group leader Prof. Hairong Zheng, 2 postdoctors and 30 postgraduates ( The research field is on Rare earth doped luminescence, plasmonics and tip-enhanced Raman spectroscopy, etc.


Zhang C J, Zhang C Y, Zhang Z L, He T, Mi X H et al. Self-suspended rare-earth doped up-conversion luminescent waveguide: propa-gating and directional radiation. Opto-Electron Adv 3, 190045 (2020).