NaYF4∶Eu nanorods with high aspect ratios are elaborated and optically trapped using dual fiber optical tweezers in a counterpropagating geometry.High trapping efficiency is observed using converging beams,emitted from diffractive Fresnel lenses directly 3D printed onto cleaved fiber facets.Stable nanorod trapping and alignment are reported for a fiber-to-fiber distance of 200 pm and light powers down to 10 mW.Trapping of nanorod clusters containing one to three nanorods and the coupling of nanorod motion in both axial and transverse directions are considered and discussed.The europium emission is studied by polarization-resolved spectroscopy with particu-lar emphasis on the magnetic and electric dipole transitions.The respective σ and π orientations of the different emission lines are determined.The angles with respect to the nanorod axes of the corresponding magnetic and electric dipoles are calculated.Mono-exponential emission decay with decay time of 4-5 ms is reported.It is shown that the nanorod orientation can be determined by purely spectroscopic means.

Université Grenoble Alpes,CNRS,Institut Néel,38000 Grenoble,France;th Physics Institute and Research Center SCoPE,University of Stuttgart,70569 Stuttgart,Germany;Université Paris Saclay,CNRS,Laboratoire de Physique de la Matière Condensée,école Polytechnique,91128 Palaiseau,France;Institute of Applied Optics and Research Center SCoPE,University of Stuttgart,70569 Stuttgart,Germany;Okinawa Institute of Science and Technology Graduate University,Okinawa 904-0495,Japan

[1]AASHUTOSH KUMAR;ASA ASADOLLAHBAIK;JEONGMO KIM;KHALID LAHLIL;SIMON THIELE;ALOIS M.HERKOMMER;SíLE NIC CHORMAIC;JONGWOOK KIM;THIERRY GACOIN;HARALD GIESSEN;JOCHEN FICK-.Emission spectroscopy of NaYF4∶Eu nanorods optically trapped by Fresnel lens fibers)[J].光子学研究（英文）,2022(02):332-339

counterpropagating

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