title: Phonon-Assisted Population Inversion in Lanthanide-Doped Upconversion Ba2LaF7Nanocrystals in Glass-Ceramics.
abstract: The effective population inversion of2H11/2from4S3/2state of Er3+ions can be achieved through the annihilation of phonons; random lasing action from BLF films embedded with Yb3+/Er3+codoped BLF nanocrystals is demonstrated and high ambient temperature (>433 K) operation lasers with a very low excitation threshold (<530 nJ cm-2) are realized.
authors.affiliation: Department of Applied Physics, The Hong Kong Polytechnic University, Kowloon, Hong Kong.|College of Materials Science and Engineering, Kunming University of Science and Technology, Kunming, 650093, China.
authors.forename: Xuhui
authors.initials: X
authors.lastname: Xu
authors.affiliation: Department of Applied Physics, The Hong Kong Polytechnic University, Kowloon, Hong Kong.|Shenzhen Key Laboratory of Laser Engineering, College of Optoelectronic Engineering, Shenzhen University, Shenzhen, 518060, China.
authors.forename: Wenfei
authors.initials: W
authors.lastname: Zhang
authors.affiliation: Department of Applied Physics, The Hong Kong Polytechnic University, Kowloon, Hong Kong.
authors.forename: Decheng
authors.initials: D
authors.lastname: Yang
authors.affiliation: Department of Applied Physics, The Hong Kong Polytechnic University, Kowloon, Hong Kong.
authors.forename: Wei
authors.initials: W
authors.lastname: Lu
authors.affiliation: College of Materials Science and Engineering, Kunming University of Science and Technology, Kunming, 650093, China.
authors.forename: Jianbei
authors.initials: J
authors.lastname: Qiu
authors.affiliation: Department of Applied Physics, The Hong Kong Polytechnic University, Kowloon, Hong Kong. apsfyu@polyu.edu.hk, sfyu21@hotmail.com.
authors.forename: Siu Fung
authors.initials: SF
authors.lastname: Yu
keywords: phonon-assisted population inversion; random cavities; rare-earth doped nanoparticles; self-cooling; upconversion lasing, nanocrystals