Ultralow-threshold, continuous-wave upconverting lasing from subwavelength plasmons

• Published in: Nature materials Vol. 18; no. 11; pp. 1172 - 1176
• Main Authors: Fernandez-Bravo, Angel, Wang, Danqing, Barnard, Edward S., Teitelboim, Ayelet, Tajon, Cheryl, Guan, Jun, Schatz, George C., Cohen, Bruce E., Chan, Emory M., Schuck, P. James, Odom, Teri W.
• Format: Journal Article
• Language: English
• Published: London Nature Publishing Group UK 01.11.2019; Nature Publishing Group; Springer Nature - Nature Publishing Group
• Subjects: 639/301; 639/624; 639/925; Biomaterials; Chemistry and Materials Science; Coherent light; Condensed Matter Physics; Continuous radiation; Electronic devices; Erbium; Holes; Lasers; Lasing; Letter; Low temperature; MATERIALS SCIENCE; Nanoparticles; Nanotechnology; Near fields; Optical and Electronic Materials; Optical Phenomena; Optical pumping; Optoelectronic devices; OTHER INSTRUMENTATION; Photonics; Photons; Plasmons; Silver; Temperature; Thermal instability; Ytterbium
• ISSN: 1476-1122; 1476-4660
• DOI: 10.1038/s41563-019-0482-5

Miniaturized lasers are an emerging platform for generating coherent light for quantum photonics, in vivo cellular imaging, solid-state lighting and fast three-dimensional sensing in smartphones 1 – 3 . Continuous-wave lasing at room temperature is critical for integration with opto-electronic devices and optimal modulation of optical interactions 4 , 5 . Plasmonic nanocavities integrated with gain can generate coherent light at subwavelength scales 6 – 9 , beyond the diffraction limit that constrains mode volumes in dielectric cavities such as semiconducting nanowires 10 , 11 . However, insufficient gain with respect to losses and thermal instabilities in nanocavities has limited all nanoscale lasers to pulsed pump sources and/or low-temperature operation 6 – 9 , 12 – 15 . Here, we show continuous-wave upconverting lasing at room temperature with record-low thresholds and high photostability from subwavelength plasmons. We achieve selective, single-mode lasing from Yb 3+ /Er 3+ -co-doped upconverting nanoparticles conformally coated on Ag nanopillar arrays that support a single, sharp lattice plasmon cavity mode and greater than wavelength λ /20 field confinement in the vertical dimension. The intense electromagnetic near-fields localized in the vicinity of the nanopillars result in a threshold of 70 W cm −2 , orders of magnitude lower than other small lasers. Our plasmon-nanoarray upconverting lasers provide directional, ultra-stable output at visible frequencies under near-infrared pumping, even after six hours of constant operation, which offers prospects in previously unrealizable applications of coherent nanoscale light. Plasmonic array nanolasers with Yb 3+ /Er 3+ -co-doped upconverting nanoparticles exhibit directional single-mode emission, with ultra-stable output over hours and with ultralow-threshold under continuous-wave pumping.