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Continuous-wave upconverting nanoparticle microlasers


Reducing the size of lasers to microscale dimensions enables new technologies1 that are specifically tailored for operation in confined spaces ranging from ultra-high-speed microprocessors2 to live brain tissue3. However, reduced cavity sizes increase optical losses and require greater input powers to reach lasing thresholds. Multiphoton-pumped lasers4,5,6,7 that have been miniaturized using nanomaterials such as lanthanide-doped upconverting nanoparticles (UCNPs)8 as lasing media require high pump intensities to achieve ultraviolet and visible emission and therefore operate under pulsed excitation schemes. Here, we make use of the recently described energy-looping excitation mechanism in Tm3+-doped UCNPs9 to achieve continuous-wave upconverted lasing action in stand-alone microcavities at excitation fluences as low as 14 kW cm−2. Continuous-wave lasing is uninterrupted, maximizing signal and enabling modulation of optical interactions10. By coupling energy-looping nanoparticles to whispering-gallery modes of polystyrene microspheres, we induce stable lasing for more than 5 h at blue and near-infrared wavelengths simultaneously. These microcavities are excited in the biologically transmissive second near-infrared (NIR-II) window and are small enough to be embedded in organisms, tissues or devices. The ability to produce continuous-wave lasing in microcavities immersed in blood serum highlights practical applications of these microscale lasers for sensing and illumination in complex biological environments.

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Fig. 1: Use of microsphere cavity modes and ELNPs for achieving CW, upconverting lasing at low powers.
Fig. 2: Upconverting microlaser structure and WGM properties.
Fig. 3: Upconverting microlaser characterization.
Fig. 4: ELNP energy transfer and emission mechanisms.
Fig. 5: Lasing in aqueous environments, temperature sensing calibration, characterization of microlaser temperature versus pump power, and evaluation of laser stability.


  1. Hill, M. T. & Gather, M. C. Advances in small lasers. Nat. Photon. 8, 908–918 (2014).

    Article  Google Scholar 

  2. Moss, D. J., Morandotti, R., Gaeta, A. L. & Lipson, M. New CMOS-compatible platforms based on silicon nitride and Hydex for nonlinear optics. Nat. Photon. 7, 597–607 (2013).

    Article  Google Scholar 

  3. Kim, T.-i et al. Injectable, cellular-scale optoelectronics with applications for wireless optogenetics. Science 340, 211–216 (2013).

    Article  Google Scholar 

  4. Jin, L. M., Chen, X., Siu, C. K., Wang, F. & Yu, S. F. Enhancing multiphoton upconversion from NaYF4:Yb/Tm@NaYF4 core−shell nanoparticles via the use of laser cavity. ACS Nano 11, 843–849 (2016).

    Article  Google Scholar 

  5. Zhu, H. et al. Amplified spontaneous emission and lasing from lanthanide-doped up-conversion nanocrystals. ACS Nano 7, 11420–11426 (2013).

    Article  Google Scholar 

  6. Chen, X. et al. Confining energy migration in upconversion nanoparticles towards deep ultraviolet lasing. Nat. Commun. 7, 1–6 (2016).

    Google Scholar 

  7. Li, M. et al. Ultralow-threshold multiphoton-pumped lasing from colloidal nanoplatelets in solution. Nat. Commun. 6, 8513 (2015).

    Article  Google Scholar 

  8. Zhou, B., Shi, B., Jin, D. & Liu, X. Controlling upconversion nanocrystals for emerging applications. Nat. Nanotech. 10, 924–936 (2015).

    Article  Google Scholar 

  9. Levy, E. S. et al. Energy-looping nanoparticles: harnessing excited-state absorption for deep-tissue imaging. ACS Nano 10, 8423–8433 (2016).

    Article  Google Scholar 

  10. Grim, J. Q. et al. Continuous-wave biexciton lasing at room temperature using solution-processed quantum wells. Nat. Nanotech. 9, 891–895 (2014).

    Article  Google Scholar 

  11. 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  Google Scholar 

  12. Dexter, D. L. Possibility of luminescent quantum yields greater than unity. Phys. Rev. 108, 630–633 (1957).

    Article  Google Scholar 

  13. Ovsyakin, V. V. & Feofilov, P. P. Cooperative sensitization of luminescence in crystals activated with rare earth ions. JETP Lett. Engl. 4, 317–318 (1966).

    Google Scholar 

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

    Article  Google Scholar 

  15. Johnson, L. F. & Guggenheim, H. J. Infrared-pumped visible laser. Appl. Phys. Lett. 19, 44–47 (1971).

    Article  Google Scholar 

  16. Grubb, S. G., Bennett, K. W., Cannon, R. S. & Humer, W. F. CW room-temperature blue upconversion fibre laser. Electron. Lett. 28, 1243–1244 (1992).

    Article  Google Scholar 

  17. Xie, P. & Gosnell, T. R. Room-temperature upconversion fiber laser tunable in the red, orange, green, and blue spectral regions. Opt. Lett. 20, 1014–1016 (1995).

    Article  Google Scholar 

  18. Bunzli, J.-C. G. & Piguet, C. Taking advantage of luminescent lanthanide ions. Chem. Soc. Rev. 34, 1048–1077 (2005).

    Article  Google Scholar 

  19. Strutt, J. W. B. R. The Theory of Sound 2nd edn, revised and enlarged (Macmillan, London, 1894).

  20. Fujiwara, H. & Sasaki, K. Upconversion lasing of a thulium-ion-doped fluorozirconate glass microsphere. J. Appl. Phys. 86, 2385–2388 (1999).

    Article  Google Scholar 

  21. Scotognella, F., Monguzzi, A., Meinardi, F. & Tubino, R. DFB laser action in a flexible fully plastic multilayer. Phys. Chem. Chem. Phys. 12, 337–340 (2010).

    Article  Google Scholar 

  22. Chen, G., Qiu, H., Prasad, P. N. & Chen, X. Upconversion nanoparticles: design, nanochemistry, and applications in theranostics. Chem. Rev. 114, 5161–5214 (2014).

    Article  Google Scholar 

  23. Idris, N. M. et al. In vivo photodynamic therapy using upconversion nanoparticles as remote-controlled nanotransducers. Nat. Med. 18, 1580–1585 (2012).

    Article  Google Scholar 

  24. Wu, X. et al. Dye-sensitized core/active shell upconversion nanoparticles for optogenetics and bioimaging applications. ACS Nano 10, 1060–1066 (2016).

    Article  Google Scholar 

  25. Niu, W. et al. 3-Dimensional photonic crystal surface enhanced upconversion emission for improved near-infrared photoresponse. Nanoscale 6, 817–824 (2014).

    Article  Google Scholar 

  26. Ioppolo, T. & Manzo, M. Dome-shaped whispering gallery mode laser for remote wall temperature sensing. Appl. Opt. 53, 5065 (2014).

    Article  Google Scholar 

  27. Fan, F. et al. Continuous-wave lasing in colloidal quantum dot solids enabled by facet-selective epitaxy. Nature 544, 75–79 (2017).

    Article  Google Scholar 

  28. Yang, A. H. J. et al. Optical manipulation of nanoparticles and biomolecules in sub-wavelength slot waveguides. Nature 457, 71–75 (2009).

    Article  Google Scholar 

  29. Funk, D. S., Eden, J. G., Osinski, J. S. & Lu, B. Green, holmium-doped upconversion fibre laser pumped by red semiconductor laser. Electron. Lett. 33, 1958–1960 (1997).

    Article  Google Scholar 

  30. Sanders, S., Waarts, R. G., Mehuys, D. G. & Welch, D. F. Laser diode pumped 106 mW blue upconversion fiber laser. Appl. Phys. Lett. 67, 1815–1817 (1995).

    Article  Google Scholar 

  31. Dennis, M. L., Dixon, J. W. & Aggarwal, I. High power upconversion lasing at 810 nm, in Tm-ZBLAN fibre. Electron. Lett. 30, 136–137 (1994).

    Article  Google Scholar 

  32. Xing, G. et al. Ultralow-threshold two-photon pumped amplified spontaneous emission and lasing from seeded CdSe/CdS nanorod heterostructures. ACS Nano 6, 10835–10844 (2012).

    Article  Google Scholar 

  33. Yu, J. et al. Confinement of pyridinium hemicyanine dye within an anionic metal–organic framework for two-photon-pumped lasing. Nat. Commun. 4, 1–7 (2013).

    Google Scholar 

  34. He, G. S., Bhawalkar, J. D., Zhao, C. F., Park, C. K. & Prasad, P. N. Two-photon-pumped cavity lasing in a dye-solution-filled hollow-fiber system. Opt. Lett. 20, 2393–2395 (1995).

    Article  Google Scholar 

  35. Fan, H. H., Guo, L., Li, K. F., Wong, M. S. & Cheah, K. W. Exceptionally strong multiphoton-excited blue photoluminescence and lasing from ladder-type oligo(p-phenylene)s. J. Am. Chem. Soc. 134, 7297–7300 (2012).

    Article  Google Scholar 

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The authors thank E. Wong for technical support. This work was performed at the Molecular Foundry and was supported by the Office of Science, Office of Basic Energy Sciences, of the US Department of Energy under contract no. DE-AC02-05CH11231. This research was in part funded under the target program no. 0115РК03029 “NU-Berkeley strategic initiative in warm-dense matter, advanced materials and energy sources for 2014-2018” from the Ministry of Education and Science of the Republic of Kazakhstan. Portions of this research were supported by the Global Research Laboratory (GRL) Program through the National Research Foundation of Korea (NRF) funded by the Ministry of Science and ICT (no. 2016911815).

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Authors and Affiliations



The scientific concepts, ideas and experimental designs were the result of interactions and discussions between A.F.B., N.J.B., E.S.L, L.M., F.S., B.E.C., P.J.S. and E.M.C. E.M.C., E.S.L, C.A.T. and B.T. synthesized the nanoparticles, and A.F.B., E.S.L., L.M., B.E.C. and E.M.C. fabricated the microlasers. A.F.B., K.Y., E.S.B, N.J.B., E.S.L., L.M. and F.S. conducted the spectroscopic measurements. K.Y., K.B. and E.M.C. performed the theoretical modelling. M.V.A., A.F.B. and S.A. conducted the electron microscopy. A.F.B., B.E.C., E.M.C. and P.J.S. wrote the paper, in coordination with all the authors.

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Correspondence to Bruce E. Cohen, Emory M. Chan or P. James Schuck.

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Supplementary Information

Supplementary Figures 1–15, Supplementary Tables 1–2, Supplementary References.

Supplementary Video 1

Description: A 5 μm UCNP microlaser operating in blood serum. The lasing emission is at 800 nm, with the 1,064 nm excitation laser being filtered out in this video. The laser emission illuminates protein globules in the blood serum as they approach and pass by the optical field of the resonator.

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Fernandez-Bravo, A., Yao, K., Barnard, E.S. et al. Continuous-wave upconverting nanoparticle microlasers. Nature Nanotech 13, 572–577 (2018).

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