title: Assessing Single Upconverting Nanoparticle Luminescence by Optical Tweezers.
abstract: We report on stable, long-term immobilization and localization of a single colloidal Er(3+)/Yb(3+) codoped upconverting fluorescent nanoparticle (UCNP) by optical trapping with a single infrared laser beam. Contrary to expectations, the single UCNP emission differs from that generated by an assembly of UCNPs. The experimental data reveal that the differences can be explained in terms of modulations caused by radiation-trapping, a phenomenon not considered before but that this work reveals to be of great relevance.
authors.affiliation: †Fluorescence Imaging Group, Departamento de Física de Materiales, Modulo 4, Universidad Autónoma de Madrid, C/Francisco Tomás y Valiente 7, Madrid 28049, Spain.
authors.forename: P
authors.initials: P
authors.lastname: Rodríguez-Sevilla
authors.affiliation: †Fluorescence Imaging Group, Departamento de Física de Materiales, Modulo 4, Universidad Autónoma de Madrid, C/Francisco Tomás y Valiente 7, Madrid 28049, Spain.
authors.forename: H
authors.initials: H
authors.lastname: Rodríguez-Rodríguez
authors.affiliation: ‡Dipartimento di Biotecnologie, Università di Verona and INSTM, UdR Verona, Ca' Vignal, Strada Le Grazie 15, I-37134 Verona, Italy.
authors.forename: M
authors.initials: M
authors.lastname: Pedroni
authors.affiliation: ‡Dipartimento di Biotecnologie, Università di Verona and INSTM, UdR Verona, Ca' Vignal, Strada Le Grazie 15, I-37134 Verona, Italy.
authors.forename: A
authors.initials: A
authors.lastname: Speghini
authors.affiliation: ‡Dipartimento di Biotecnologie, Università di Verona and INSTM, UdR Verona, Ca' Vignal, Strada Le Grazie 15, I-37134 Verona, Italy.
authors.forename: M
authors.initials: M
authors.lastname: Bettinelli
authors.affiliation: †Fluorescence Imaging Group, Departamento de Física de Materiales, Modulo 4, Universidad Autónoma de Madrid, C/Francisco Tomás y Valiente 7, Madrid 28049, Spain.
authors.forename: J García
authors.initials: JG
authors.lastname: Solé
authors.affiliation: †Fluorescence Imaging Group, Departamento de Física de Materiales, Modulo 4, Universidad Autónoma de Madrid, C/Francisco Tomás y Valiente 7, Madrid 28049, Spain.
authors.forename: D
authors.initials: D
authors.lastname: Jaque
authors.affiliation: †Fluorescence Imaging Group, Departamento de Física de Materiales, Modulo 4, Universidad Autónoma de Madrid, C/Francisco Tomás y Valiente 7, Madrid 28049, Spain.
authors.forename: P
authors.initials: P
authors.lastname: Haro-González
keywords: optical tweezers; single particle fluorescence; upconverting nanoparticle