title: A fusion-spliced near-field optical fiber probe using photonic crystal fiber for nanoscale thermometry based on fluorescence-lifetime measurement of quantum dots.
abstract: We have developed a novel nanoscale temperature-measurement method using fluorescence in the near-field called fluorescence near-field optics thermal nanoscopy (Fluor-NOTN). Fluor-NOTN enables the temperature distributions of nanoscale materials to be measured in vivo/in situ. The proposed method measures temperature by detecting the temperature dependent fluorescence lifetimes of Cd/Se quantum dots (QDs). For a high-sensitivity temperature measurement, the auto-fluorescence generated from a fiber probe should be reduced. In order to decrease the noise, we have fabricated a novel near-field optical-fiber probe by fusion-splicing a photonic crystal fiber (PCF) and a conventional single-mode fiber (SMF). The validity of the novel fiber probe was assessed experimentally by evaluating the auto-fluorescence spectra of the PCF. Due to the decrease of auto-fluorescence, a six- to ten-fold increase of S/N in the near-field fluorescence lifetime detection was achieved with the newly fabricated fusion-spliced near-field optical fiber probe. Additionally, the near-field fluorescence lifetime of the quantum dots was successfully measured by the fabricated fusion-spliced near-field optical fiber probe at room temperature, and was estimated to be 10.0 ns.
authors.affiliation: School of Integrated Design Engineering, Keio University, Kanagawa 223-8522, Japan. fujii@naga.sd.keio.ac.jp
authors.forename: Takuro
authors.initials: T
authors.lastname: Fujii
authors.forename: Yoshihiro
authors.initials: Y
authors.lastname: Taguchi
authors.forename: Toshiharu
authors.initials: T
authors.lastname: Saiki
authors.forename: Yuji
authors.initials: Y
authors.lastname: Nagasaka
mesh_terms: D005453:Fluorescence; D015335:Molecular Probes; D036103:Nanotechnology; D055100:Optical Fibers; D045663:Quantum Dots; D013696:Temperature
chemical_list: D015335:Molecular Probes