Low threshold lasing emissions from a single upconversion nanocrystal

• Published in: Nature communications Vol. 11; no. 1; p. 6156
• Main Authors: Shang, Yunfei, Zhou, Jiajia, Cai, Yangjian, Wang, Fan, Fernandez-Bravo, Angel, Yang, Chunhui, Jiang, Lei, Jin, Dayong
• Format: Journal Article
• Language: English
• Published: London Nature Publishing Group 01.12.2020; Nature Publishing Group UK; Nature Portfolio
• Subjects: Brightness; Continuous radiation; Cross relaxation; Emissions; Emitters; Emitters (electron); Lasing; Luminescence; Nanocrystals; Nanomaterials; Nanoparticles; Nanotechnology; Population inversion; Quenching; Room temperature; Upconversion; Wave excitation; Wavelengths
• ISSN: 2041-1723; 2041-1723
• DOI: 10.1038/s41467-020-19797-4

Abstract Cross-relaxation among neighboring emitters normally causes self-quenching and limits the brightness of luminescence. However, in nanomaterials, cross-relaxation could be well-controlled and employed for increasing the luminescence efficiency at specific wavelengths. Here we report that cross-relaxation can modulate both the brightness of single upconversion nanoparticles and the threshold to reach population inversion, and both are critical factors in producing the ultra-low threshold lasing emissions in a micro cavity laser. By homogenously coating a 5-μm cavity with a single layer of nanoparticles, we demonstrate that doping Tm 3+ ions at 2% can facilitate the electron accumulation at the intermediate state of 3 H 4 level and efficiently decrease the lasing threshold by more than one order of magnitude. As a result, we demonstrate up-converted lasing emissions with an ultralow threshold of continuous-wave excitation of ~150 W/cm 2 achieved at room temperature. A single nanoparticle can lase with a full width at half-maximum as narrow as ~0.45 nm.