title: Amplified spontaneous emission and lasing from lanthanide-doped up-conversion nanocrystals.
abstract: Lanthanide-doped nanocrystals (NCs), which found applications in bioimaging and labeling, have recently demonstrated significant improvement in up-conversion efficiency. Here, we report the first up-conversion multicolor microcavity lasers by using NaYF4:Yb/Er@NaYF4 core-shell NCs as the gain medium. It is shown that the optical gain of the NCs, which arises from the 2- and 3-photon up-conversion processes, can be maximized via sequential pulses pumping. Amplified spontaneous emission is observed from a Fabry-Perot cavity containing the NCs dispersed in cyclohexane solution. By coating a drop of silica resin containing the NCs onto an optical fiber, a microcavity with a bottle-like geometry is fabricated. It is demonstrated that the microcavity supports lasing emission through the formation of whispering gallery modes.
authors.affiliation: Department of Applied Physics, The Hong Kong Polytechnic University , Kowloon, Hong Kong SAR, China.
authors.forename: Hai
authors.initials: H
authors.lastname: Zhu
authors.forename: Xian
authors.initials: X
authors.lastname: Chen
authors.forename: Li Min
authors.initials: LM
authors.lastname: Jin
authors.forename: Qi Jie
authors.initials: QJ
authors.lastname: Wang
authors.forename: Feng
authors.initials: F
authors.lastname: Wang
authors.forename: Siu Fung
authors.initials: SF
authors.lastname: Yu
mesh_terms: D003510:Cyclohexanes / Q000737:chemistry; D004867:Equipment Design; D005459:Fluorides / Q000737:chemistry; D028581:Lanthanoid Series Elements / Q000737:chemistry*; D007834:Lasers; D008027:Light; D046529:Microscopy, Electron, Transmission; D053758:Nanoparticles / Q000737:chemistry*; D036103:Nanotechnology / Q000379:methods*; D055095:Optics and Photonics; D010777:Photochemistry; D017785:Photons; D012822:Silicon Dioxide / Q000737:chemistry; D012964:Sodium / Q000737:chemistry
chemical_list: D003510:Cyclohexanes; D028581:Lanthanoid Series Elements; C506365:Cyclohexane; D012822:Silicon Dioxide; D012964:Sodium; D005459:Fluorides