Near-infrared excited rare-earth (RE)-doped up-conversion (UC)-luminescent materials have attracted enormous attention because of their unique emission properties, such as narrow emission bands, long luminescence lifetimes, and multiple colors. However, current development of RE-doped luminescent material is hindered by weak and narrowband absorption problems and low photon-conversion quantum efficiencies. In addition to conventional approaches to enhance fluorescence intensity, controlling emission directivity to improve detection efficiency has become a promising approach to obtain higher luminescence brightnesses. In this paper, a self-suspended RE-doped UC luminescent waveguide is designed to realize directional emissions. Benefitting from the special morphology of the crown-like NaYF4:Yb3+/Er3+ microparticle, the points contact between the waveguide and substrate can be obtained to decrease energy loss. An attractive UC luminescent pattern accompanied by powerful and controllable directional emissions is observed, and the spatial emission angle and intensity distribution are explored and analyzed in detail by introducing Fourier imaging detection and simulation. This work provides a new method for achieving controllable directional fluorescence emissions and obtaining improved detection efficiency by narrowing emission directivity, which has potential applications in 3-dimensional displays and micro-optoelectronic devices, especially when fabricating self-fluorescence micron lasers.
Self-suspended rare-earth doped up-conversion luminescent waveguide: propagating and directional radiation
1. Wu Y M, Xu J H, Poh E T, Liang L L, Liu H L et al. Upconversion superburst with sub-2 μs lifetime. Nat Nanotechnol 14, 1110–1115 (2019).
2. Zhu X H, Zhang J, Liu J L, Zhang Y. Recent progress of rare- earth doped upconversion nanoparticles: synthesis, optimization, and applications. Adv Sci 6, 1901358 (2019).
3. Chan E M. Combinatorial approaches for developing upconverting nanomaterials: high-throughput screening, modeling, and applications. Chem Soc Rev 44, 1653–1679 (2015).
4. Xu W, Chen X, Song H W. Upconversion manipulation by local electromagnetic field. Nano Today 17, 54–78 (2017).
5. Zhou B, Shi B Y, Jin D Y, Liu X G. Controlling upconversion nanocrystals for emerging applications. Nat Nanotechnol 10, 924–936 (2015).
6. Wang F, Liu X G. Recent advances in the chemistry of lanthanide-doped upconversion nanocrystals. Chem Soc Rev 38, 976–989 (2009).
7. Gu Y Y, Guo Z Y, Yuan W, Kong M Y, Liu Y L et al. High-sensitivity imaging of time-domain near-infrared light transducer. Nat Photonics 13, 525–531 (2019).
8. Han S Y, Deng R R, Xie X J, Liu X G. Enhancing luminescence in lanthanide-doped upconversion nanoparticles. Angew Chem Int Ed Engl 53, 11702–11715 (2014).
9. Liu G K. Advances in the theoretical understanding of photon upconversion in rare-earth activated nanophosphors. Chem Soc Rev 44, 1635–1652 (2015).
10. Zhao J B, Jin D Y, Schartner E P, Lu Y Q, Liu Y Q et al. Single-nanocrystal sensitivity achieved by enhanced upconversion luminescence. Nat Nanotechnol 8, 729–734 (2013).
11. Aouani H, Mahboub O, Bonod N, Devaux E, Popov E et al. Bright unidirectional fluorescence emission of molecules in a nanoaperture with plasmonic corrugations. Nano Lett 11, 637–644 (2011).
12. Hu Y Q, Shao Q Y, Dong Y, Jiang J Q. Energy loss mechanism of upconversion core/shell nanocrystals. J Phys Chem C 123, 22674–22679 (2019).
13. Wang F, Han Y, Lim C S, Lu Y H, Wang J et al. Simultaneous phase and size control of upconversion nanocrystals through lanthanide doping. Nature 463, 1061–1065 (2010).
14. Mao C C, Min K, Bae K, Cho S, Xu T et al. Enhanced upconversion luminescence by two-dimensional photonic crystal structure. ACS Photonics 6, 1882–1888 (2019).
15. Bulgarini G, Reimer M E, Bouwes Bavinck M, J?ns K D, Dalacu D et al. Nanowire waveguides launching single photons in a Gaussian mode for ideal fiber coupling. Nano Lett 14, 4102–4106 (2014).
16. Li Z P, Hao F, Huang Y Z, Fang Y R, Nordlander P et al. Directional light emission from propagating surface plasmons of silver nanowires. Nano Lett 9, 4383–4386 (2009).
17. Shegai T, Chen S, Miljkovi? V D, Zengin G, Johansson P et al. A bimetallic nanoantenna for directional colour routing. Nat Commun 2, 481 (2011).
18. Fang Z Y, Fan L R, Lin C F, Zhang D, Meixner A J et al. Plasmonic coupling of bow tie antennas with Ag nanowire. Nano Lett 11, 1676–1680 (2011).
19. Wang Z X, Wei H, Pan D, Xu H X. Controlling the radiation direction of propagating surface plasmons on silver nanowires. Laser Photonics Rev 8, 596–601 (2014).
20. Mongillo M, Spathis P, Katsaros G, Gentile P, De Franceschi S. Multifunctional devices and logic gates with undoped silicon nanowires. Nano Lett 12, 3074–3079 (2012).
21. Huang S Z, Chen H, He T, Zhang C J, Zhang C Y et al. High-performance upconversion luminescent waveguide using a rare-earth doped microtube with beveled ends. J Mater Chem C 7, 12704–12708 (2019).
22. Han Q Y, Zhang C Y, Wang C, Wang Z J, Li C X et al. Unique adjustable UC luminescence pattern and directional radiation of peculiar-shaped NaYF4: Yb3+/Er3+ microcrystal particle. Sci Rep 7, 5371 (2017).
23. Haas J, Catalan E V, Piron P, Karlsson M, Mizaikoff B. Infrared spectroscopy based on broadly tunable quantum cascade lasers and polycrystalline diamond waveguides. Analyst 143, 5112–5119 (2018).
24. Bing C, Sun T Y, Qiao X S, Fan X P, Wang F. Directional light emission in a single NaYF4 microcrystal via photon upconversion. Adv Opt Mater 3, 1577–1581 (2015).
25. Xu W, Lee T K, Moon B S, Zhou D L, Song H W et al. Spectral and spatial characterization of upconversion luminescent nanocrystals as nanowaveguides. Nanoscale 9, 9238–9245 (2017).
26. Debije M G, Verbunt P P C, Rowan B C, Richards B S, Optics T L. Measured surface loss from luminescent solar concentrator waveguides. Appl Opt 47, 6763–6768 (2008).
27. Luan L, Sievert P R, Mu W, Hong Z, Ketterson J B. Highly directional fluorescence emission from dye molecules embedded in a dielectric layer adjacent to a silver film. New J Phys 10, 073012 (2008).
28. Dai D X, Wang Z, Bauters J F, Tien M C, Heck M J R et al. Low-loss Si3N4 arrayed-waveguide grating (de)multiplexer using nano-core optical waveguides. Opt Express 19, 14130–14136 (2011).
29. Dong B, Hua R N, Cao B S, Li Z P, He Y Y et al. Size dependence of the upconverted luminescence of NaYF4:Er, Yb microspheres for use in ratiometric thermometry. Phys Chem Chem Phys 16, 20009–20012 (2014).
30. Du P, Deng A M, Luo L H, Yu J S. Simultaneous phase and size manipulation in NaYF4:Er3+/Yb3+ upconverting nanoparticles for a non-invasion optical thermometer. New J Chem 41, 13855–13861(2017).
31. Sokolov V I, Zvyagin A V, Igumnov S M, Molchanova S I, Nazarov M M et al. Determination of the refractive index of β-NaYF4/Yb3+/Er3+/Tm3+ nanocrystals using spectroscopic refractometry. Opt Spectrosc 118, 609–613 (2015).
32. Han Q Y, Gao W, Zhang C Y, Mi X H, Zhao X et al. Tunable flower-like upconversion emission and directional red radiation in a single NaYF4:Yb3+/Tm3+ microcrystal particle. J Alloy Compd 748, 252–257 (2018).
the National Natural Science Foundation of China (Grant Nos. 11574190 and 11504224), the National Science Foundation of Shaanxi Province (Grant Nos. 2019JQ-142 and 2019JM-441), and the Fundamental Research Funds for Central Universities (Grant Nos. GK201701008, 201903013, and 2017TS013)
引用本文： 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).