title: Determining the 3D orientation of optically trapped upconverting nanorods by in situ single-particle polarized spectroscopy.
abstract: An approach to unequivocally determine the three-dimensional orientation of optically manipulated NaYF4:Er(3+),Yb(3+) upconverting nanorods (UCNRs) is demonstrated. Long-term immobilization of individual UCNRs inside single and multiple resonant optical traps allow for stable single UCNR spectroscopy studies. Based on the strong polarization dependent upconverted luminescence of UCNRs it is possible to unequivocally determine, in real time, their three-dimensional orientation when optically trapped. In single-beam traps, polarized single particle spectroscopy has concluded that UCNRs orientate parallel to the propagation axis of the trapping beam. On the other hand, when multiple-beam optical tweezers are used, single particle polarization spectroscopy demonstrated how full spatial control over UCNR orientation can be achieved by changing the trap-to-trap distance as well as the relative orientation between optical traps. All these results show the possibility of real time three-dimensional manipulation and tracking of anisotropic nanoparticles with wide potential application in modern nanobiophotonics.
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. patricia.haro@uam.es.
authors.forename: Paloma
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. patricia.haro@uam.es.
authors.forename: Lucía
authors.initials: L
authors.lastname: Labrador-Páez
authors.affiliation: Advanced Materials Engineering and Modelling Group, Wroclaw University of Technology, Wyb. Wyspianskiego 27, 50-3 70 Wroclaw, Poland.
authors.forename: Dominika
authors.initials: D
authors.lastname: Wawrzyńczyk
authors.affiliation: Advanced Materials Engineering and Modelling Group, Wroclaw University of Technology, Wyb. Wyspianskiego 27, 50-3 70 Wroclaw, Poland.
authors.forename: Marcin
authors.initials: M
authors.lastname: Nyk
authors.affiliation: Advanced Materials Engineering and Modelling Group, Wroclaw University of Technology, Wyb. Wyspianskiego 27, 50-3 70 Wroclaw, Poland.
authors.forename: Marek
authors.initials: M
authors.lastname: Samoć
authors.affiliation: Institute of Photonics and Quantum Science, Heriot Watt University, Riccarton Campus, Edinburgh EH14 4AS, UK. a.k.kar@hw.ac.uk.
authors.forename: Ajoy Kumar
authors.initials: AK
authors.lastname: Kar
authors.affiliation: Institute of Photonics and Quantum Science, Heriot Watt University, Riccarton Campus, Edinburgh EH14 4AS, UK. a.k.kar@hw.ac.uk.
authors.forename: Mark D
authors.initials: MD
authors.lastname: Mackenzie
authors.affiliation: Institute of Biological Chemistry, Biophysics and Bioengineering, School of Engineering and Physical Sciences, Heriot Watt University, Edinburgh, EH14 4AS, UK.
authors.forename: Lynn
authors.initials: L
authors.lastname: Paterson
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. patricia.haro@uam.es.
authors.forename: Daniel
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. patricia.haro@uam.es.
authors.forename: Patricia
authors.initials: P
authors.lastname: Haro-González