Skip to main content

Thank you for visiting nature.com. You are using a browser version with limited support for CSS. To obtain the best experience, we recommend you use a more up to date browser (or turn off compatibility mode in Internet Explorer). In the meantime, to ensure continued support, we are displaying the site without styles and JavaScript.

  • Letter
  • Published:

Amplified stimulated emission in upconversion nanoparticles for super-resolution nanoscopy

Nature volume 543, pages 229–233 (2017)Cite this article

Subjects

Abstract

Lanthanide-doped glasses and crystals are attractive for laser applications because the metastable energy levels of the trivalent lanthanide ions facilitate the establishment of population inversion and amplified stimulated emission at relatively low pump power1,2,3. At the nanometre scale, lanthanide-doped upconversion nanoparticles (UCNPs) can now be made with precisely controlled phase, dimension and doping level4,5. When excited in the near-infrared, these UCNPs emit stable, bright visible luminescence at a variety of selectable wavelengths6,7,8,9, with single-nanoparticle sensitivity10,11,12,13, which makes them suitable for advanced luminescence microscopy applications. Here we show that UCNPs doped with high concentrations of thulium ions (Tm3+), excited at a wavelength of 980 nanometres, can readily establish a population inversion on their intermediate metastable 3H4 level: the reduced inter-emitter distance at high Tm3+ doping concentration leads to intense cross-relaxation, inducing a photon-avalanche-like effect that rapidly populates the metastable 3H4 level, resulting in population inversion relative to the 3H6 ground level within a single nanoparticle. As a result, illumination by a laser at 808 nanometres, matching the upconversion band of the 3H4 → 3H6 transition, can trigger amplified stimulated emission to discharge the 3H4 intermediate level, so that the upconversion pathway to generate blue luminescence can be optically inhibited. We harness these properties to realize low-power super-resolution stimulated emission depletion (STED) microscopy and achieve nanometre-scale optical resolution (nanoscopy), imaging single UCNPs; the resolution is 28 nanometres, that is, 1/36th of the wavelength. These engineered nanocrystals offer saturation intensity two orders of magnitude lower than those of fluorescent probes currently employed in stimulated emission depletion microscopy, suggesting a new way of alleviating the square-root law that typically limits the resolution that can be practically achieved by such techniques.

This is a preview of subscription content, access via your institution

Access options

Buy this article

  • Purchase on Springer Link
  • Instant access to full article PDF
Buy now

Prices may be subject to local taxes which are calculated during checkout

Figure 1: Probing upconversion luminescence using dual-laser illumination.
Figure 2: Competition between absorption and stimulated emission.
Figure 3: The photon-avalanche-like process underlying enhanced population inversion.
Figure 4: Optical switching efficiency with respect to Tm doping concentration.
Figure 5: Super-resolution imaging of the highly-doped UCNPs.

Similar content being viewed by others

References

  1. Urquhart, P. Review of rare-earth doped fiber lasers and amplifiers. IEE Proc. J. Optoelectron. 135, 385–402 (1988)

    Article  ADS  CAS  Google Scholar 

  2. Stoneman, R. C. & Esterowitz, L. Efficient, broadly tunable, laser-pumped Tm-YAG and Tm-YSGG CW lasers. Opt. Lett. 15, 486–488 (1990)

    Article  ADS  CAS  Google Scholar 

  3. Jackson, S. D. Towards high-power mid-infrared emission from a fibre laser. Nat. Photon. 6, 423–431 (2012)

    Article  ADS  CAS  Google Scholar 

  4. Wang, F. et al. Simultaneous phase and size control of upconversion nanocrystals through lanthanide doping. Nature 463, 1061–1065 (2010)

    Article  ADS  CAS  Google Scholar 

  5. Liu, D. et al. Three-dimensional controlled growth of monodisperse sub-50 nm heterogeneous nanocrystals. Nat. Commun. 7, 10254 (2016)

    Article  ADS  CAS  Google Scholar 

  6. Mai, H.-X., Zhang, Y.-W., Sun, L.-D. & Yan, C.-H. Highly efficient multicolor up-conversion emissions and their mechanisms of monodisperse NaYF4: Yb,Er core and core/shell-structured nanocrystals. J. Phys. Chem. C 111, 13721–13729 (2007)

    Article  CAS  Google Scholar 

  7. Chen, G., Ohulchanskyy, T. Y., Kumar, R., Agren, H. & Prasad, P. N. Ultrasmall monodisperse NaYF4:Yb3+/Tm3+ nanocrystals with enhanced near-infrared to near-infrared upconversion photoluminescence. ACS Nano 4, 3163–3168 (2010)

    Article  CAS  Google Scholar 

  8. Wang, F. et al. Tuning upconversion through energy migration in core-shell nanoparticles. Nat. Mater. 10, 968–973 (2011)

    Article  ADS  CAS  Google Scholar 

  9. Lu, Y. et al. Tunable lifetime multiplexing using luminescent nanocrystals. Nat. Photon. 8, 33–37 (2014)

    ADS  Google Scholar 

  10. Wu, S. et al. Non-blinking and photostable upconverted luminescence from single lanthanide-doped nanocrystals. Proc. Natl Acad. Sci. USA 106, 10917–10921 (2009)

    Article  ADS  CAS  Google Scholar 

  11. Park, Y. I. et al. Nonblinking and nonbleaching upconverting nanoparticles as an optical imaging nanoprobe and T1 magnetic resonance imaging contrast agent. Adv. Mater. 21, 4467–4471 (2009)

    Article  CAS  Google Scholar 

  12. Zhao, J. et al. Single-nanocrystal sensitivity achieved by enhanced upconversion luminescence. Nat. Nanotechnol. 8, 729–734 (2013)

    Article  ADS  CAS  Google Scholar 

  13. Gargas, D. J. et al. Engineering bright sub-10-nm upconverting nanocrystals for single-molecule imaging. Nat. Nanotechnol. 9, 300–305 (2014)

    Article  ADS  CAS  Google Scholar 

  14. Joubert, M. F., Guy, S. & Jacquier, B. Model of the photon-avalanche effect. Phys. Rev. B 48, 10031–10037 (1993)

    Article  ADS  CAS  Google Scholar 

  15. Collings, B. C. & Silversmith, A. J. Avalanche up-conversion in LaF3Tm3+ . J. Lumin. 62, 271–279 (1994)

    Article  CAS  Google Scholar 

  16. Auzel, F. & Chen, Y. Photon avalanche luminescence of Er3+ ions in LiYF4 crystal. J. Lumin. 65, 45–56 (1995)

    Article  CAS  Google Scholar 

  17. Scheps, R. Upconversion laser processes. Prog. Quantum Electron. 20, 271–358 (1996)

    Article  ADS  CAS  Google Scholar 

  18. Selvin, P. R. The renaissance of fluorescence resonance energy transfer. Nat. Struct. Biol. 7, 730–734 (2000)

    Article  CAS  Google Scholar 

  19. Rabouw, F. T., den Hartog, S. A., Senden, T. & Meijerink, A. Photonic effects on the Forster resonance energy transfer efficiency. Nat. Commun. 5, 3610 (2014)

    Article  ADS  Google Scholar 

  20. Auzel, F. Upconversion and anti-Stokes processes with f and d ions in solids. Chem. Rev. 104, 139–174 (2004)

    Article  CAS  Google Scholar 

  21. Willig, K. I., Harke, B., Medda, R. & Hell, S. W. STED microscopy with continuous wave beams. Nat. Methods 4, 915–918 (2007)

    Article  CAS  Google Scholar 

  22. Leutenegger, M., Eggeling, C. & Hell, S. W. Analytical description of STED microscopy performance. Opt. Express 18, 26417–26429 (2010)

    Article  ADS  CAS  Google Scholar 

  23. Donnert, G. et al. Macromolecular-scale resolution in biological fluorescence microscopy. Proc. Natl Acad. Sci. USA 103, 11440–11445 (2006)

    Article  ADS  CAS  Google Scholar 

  24. Kolesov, R. et al. Super-resolution upconversion microscopy of praseodymium-doped yttrium aluminum garnet nanoparticles. Phys. Rev. B 84, 153413 (2011)

    Article  ADS  Google Scholar 

  25. Han, K. Y. et al. Three-dimensional stimulated emission depletion microscopy of nitrogen-vacancy centers in diamond using continuous-wave light. Nano Lett. 9, 3323–3329 (2009)

    Article  ADS  CAS  Google Scholar 

  26. Hanne, J. et al. STED nanoscopy with fluorescent quantum dots. Nat. Commun. 6, 7127 (2015)

    Article  ADS  CAS  Google Scholar 

  27. Harke, B. et al. Resolution scaling in STED microscopy. Opt. Express 16, 4154–4162 (2008)

    Article  ADS  Google Scholar 

  28. Wu, R. et al. Optical depletion mechanism of upconverting luminescence and its potential for multi-photon STED-like microscopy. Opt. Express 23, 32401–32412 (2015)

    Article  ADS  CAS  Google Scholar 

  29. Chmyrov, A. et al. Nanoscopy with more than 100,000 ‘doughnuts’. Nat. Methods 10, 737–740 (2013)

    Article  CAS  Google Scholar 

  30. Sedlmeier, A. & Gorris, H. H. Surface modification and characterization of photon-upconverting nanoparticles for bioanalytical applications. Chem. Soc. Rev. 44, 1526–1560 (2015)

    Article  CAS  Google Scholar 

  31. He, L., Ozdemir, S. K., Zhu, J., Kim, W. & Yang, L. Detecting single viruses and nanoparticles using whispering gallery microlasers. Nat. Nanotechnol. 6, 428–432 (2011)

    Article  ADS  CAS  Google Scholar 

  32. Koenderink, A. F., Alù, A. & Polman, A. Nanophotonics: shrinking light-based technology. Science 348, 516–521 (2015)

    Article  ADS  CAS  Google Scholar 

  33. Buchegger, B. et al. Stimulated emission depletion lithography with mercapto-functional polymers. ACS Nano 10, 1954–1959 (2016)

    Article  CAS  Google Scholar 

  34. Chivian, J. S., Case, W. E. & Eden, D. D. The photon avalanche: a new phenomenon in Pr3+-based infrared quantum counters. Appl. Phys. Lett. 35, 124–125 (1979)

    Article  ADS  CAS  Google Scholar 

  35. Joubert, M. F. Photon avalanche upconversion in rare earth laser materials. Opt. Mater. 11, 181–203 (1999)

    Article  ADS  CAS  Google Scholar 

  36. Goldner, P. & Pelle, F. Photon avalanche fluorescence and lasers. Opt. Mater. 5, 239–249 (1996)

    Article  ADS  CAS  Google Scholar 

Download references

Acknowledgements

This project was primarily supported by the Australian Research Council (ARC) Future Fellowship Scheme (D.J., FT 130100517), the ARC Centre of Excellence for Nanoscale BioPhotonics (CE140100003), the Natural Science Foundation of China (61428501, 31327901, 61475010), and the National Instrumentation Project of China (2013YQ03065102). Y. Lu acknowledges support from a Macquarie University Research Fellowship.

Author information

Author notes

  1. Yujia Liu, Yiqing Lu and Xusan Yang: These authors contributed equally to this work.

Authors and Affiliations

  1. Advanced Cytometry Laboratories, ARC Centre of Excellence for Nanoscale BioPhotonics (CNBP), Macquarie University, Sydney, 2109, New South Wales, Australia

    Yujia Liu, Yiqing Lu, Xianlin Zheng, Shihui Wen, Fan Wang, Xavier Vidal, Jiangbo Zhao, Deming Liu, Zhiguang Zhou, Chenshuo Ma, James A. Piper, Peng Xi & Dayong Jin

  2. Department of Physics and Astronomy, Macquarie University, Sydney, 2109, New South Wales, Australia

    Yujia Liu, Yiqing Lu, Xianlin Zheng, Fan Wang, Xavier Vidal, Jiangbo Zhao, Deming Liu, James A. Piper & Dayong Jin

  3. Department of Biomedical Engineering, College of Engineering, Peking University, Beijing, 100871, China

    Yujia Liu, Xusan Yang & Peng Xi

  4. School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai, 200241, China

    Yujia Liu

  5. Institute for Biomedical Materials and Devices (IBMD), Faculty of Science, University of Technology Sydney, Sydney, 2007, New South Wales, Australia

    Shihui Wen, Fan Wang, Zhiguang Zhou, Jiajia Zhou & Dayong Jin

Authors
  1. Yujia Liu
    View author publications

    You can also search for this author in PubMed Google Scholar

  2. Yiqing Lu
    View author publications

    You can also search for this author in PubMed Google Scholar

  3. Xusan Yang
    View author publications

    You can also search for this author in PubMed Google Scholar

  4. Xianlin Zheng
    View author publications

    You can also search for this author in PubMed Google Scholar

  5. Shihui Wen
    View author publications

    You can also search for this author in PubMed Google Scholar

  6. Fan Wang
    View author publications

    You can also search for this author in PubMed Google Scholar

  7. Xavier Vidal
    View author publications

    You can also search for this author in PubMed Google Scholar

  8. Jiangbo Zhao
    View author publications

    You can also search for this author in PubMed Google Scholar

  9. Deming Liu
    View author publications

    You can also search for this author in PubMed Google Scholar

  10. Zhiguang Zhou
    View author publications

    You can also search for this author in PubMed Google Scholar

  11. Chenshuo Ma
    View author publications

    You can also search for this author in PubMed Google Scholar

  12. Jiajia Zhou
    View author publications

    You can also search for this author in PubMed Google Scholar

  13. James A. Piper
    View author publications

    You can also search for this author in PubMed Google Scholar

  14. Peng Xi
    View author publications

    You can also search for this author in PubMed Google Scholar

  15. Dayong Jin
    View author publications

    You can also search for this author in PubMed Google Scholar

Contributions

D.J. and P.X. conceived the project. D.J., P.X. and J.A.P. supervised the research. Y. Liu, X.Y., F.W., X.Z. and Z.Z. conducted the optical experiments. S.W., J. Zhao, D.L., J. Zhou, and C.M. synthesized the upconversion nanoparticles. Y. Lu carried out the modelling. Y. Lu, Y. Liu, X.Y., X.Z., X.V., P.X. and D.J. analysed the results, prepared the figures and wrote the manuscript. All authors participated in discussion and editing of the manuscript.

Corresponding authors

Correspondence to Yiqing Lu, Peng Xi or Dayong Jin.

Ethics declarations

Competing interests

The authors declare no competing financial interests.

Additional information

Reviewer Information Nature thanks Y. D. Suh and the other anonymous reviewer(s) for their contribution to the peer review of this work.

Extended data figures and tables

Extended Data Figure 1 Optical layout of the dual-laser confocal/super-resolution microscope for probing NaYF4:Yb,Tm nanocrystals.

SMF, single-mode fibre; PMF, polarization-maintaining fibre; MMF, multi-mode fibre; DC1 and DC2, dichroic filters; L1, L2 and L3, collimation/collection lenses; HWP, half-wave plate; QWP, quarter-wave plate; VPP, vortex phase plate; SPAD, single-photon avalanche diode; M, mirror.

Extended Data Figure 2 Upconversion emission spectra of 8% (left) and 1% (right) Tm-doped UCNPs.

The 980 nm and 808 nm laser powers measured at the objective back aperture were 1 and 10 mW, respectively.

Extended Data Figure 3 Transient responses of 650 nm upconversion emission under synchronous 980 nm and 808 nm pulses.

Left, 8% Tm-doped UCNPs; right, 1% Tm-doped UCNPs. The 980 nm laser power was fixed at 1 mW, while the 808 nm laser power was varied from 0 to 40 mW (both measured at the objective back aperture).

Extended Data Figure 4 Modelling of the photon-avalanche-like process in upconversion materials.

a, Simplified three-level energy diagram of an upconversion system containing sensitizers and emitters. b, Block diagram illustrating photon avalanche as a feedback process, with its type (positive or negative) determined by the sign of (k – bW3). c, Numerical simulation of the emitter populations based on the rate parameters reported previously14. Comparison between non-resonant ground-level pumping (top) and resonant ground-level pumping (bottom) shows that the threshold occurs only if non-resonant ground-level pumping is employed. See Methods for details.

Extended Data Figure 5 Simulation of the Yb–Tm upconversion system.

a, Energy level diagram used for rate equation modelling. b, Rate parameters simulated for the 8% Tm-doped UCNPs. c, Comparison between the simulation and the experimental results for the 8% Tm-doped UCNPs under dual-laser excitation with different pulse sequences (left and right). d, Numerical simulation of the emitter populations under 980 nm pumping only, using the obtained c1 value (left), and by artificially setting c1 = 1 to reveal the threshold (right). Details of rate equation modelling are given in Methods.

Extended Data Figure 6 TEM images of the NaYF4:Yb,Tm nanocrystals.

The Yb doping concentration was fixed at 20 mol%, and a–j, the Tm doping concentrations are respectively 0.5, 1, 1.5, 2, 2.5, 3, 3.5, 4, 6 and 8 mol%. All nanocrystals have average sizes around 40 nm. Scale bar, 100 nm.

Extended Data Figure 7 Simulation of the optical switching at 455 nm for 8% Tm-doped UCNPs.

a, The 455 nm depletion ratio as a function of the 808 nm probing rate, which is simulated using the rate parameters listed in Extended Data Fig. 5b. The curve fits well to 1/(1 + I/IS) except for the high power range. b, Emitter populations as a function of time, again simulated using the rate parameters listed in Extended Data Fig. 5b. The 980 nm pumping is turned on at time = 0 s, while the 808 nm probing is turned on at time = 0.5 ms. Note the overlap between n1 (3H6 ground level) and n3 (3H4 intermediate level) once the 808 nm probing is turned on.

Extended Data Figure 8 Time-series upconversion-STED images recorded for the same sample area under continuous laser excitation and scanning.

The sample slide contains 40-nm UCNPs with 8% Tm and 20% Yb. The 455 nm upconversion emission photon count is colour coded. The 980 and 808 nm laser powers at the objective back aperture were 1 and 30 mW, respectively. The scan step is 20 nm and the pixel dwell time is 4 ms. Scale bar, 500 nm.

PowerPoint slides

Rights and permissions

Reprints and permissions

About this article

Check for updates. Verify currency and authenticity via CrossMark

Cite this article

Liu, Y., Lu, Y., Yang, X. et al. Amplified stimulated emission in upconversion nanoparticles for super-resolution nanoscopy. Nature 543, 229–233 (2017). https://doi.org/10.1038/nature21366

Download citation

  • Received:

  • Accepted:

  • Published:

  • Issue Date:

  • DOI: https://doi.org/10.1038/nature21366

This article is cited by

Comments

By submitting a comment you agree to abide by our Terms and Community Guidelines. If you find something abusive or that does not comply with our terms or guidelines please flag it as inappropriate.

Search

Advanced search

Quick links

Nature Briefing

Sign up for the Nature Briefing newsletter — what matters in science, free to your inbox daily.

Get the most important science stories of the day, free in your inbox. Sign up for Nature Briefing