Effect of the Photoexcitation Wavelength and Polarization on the Generated Heat by a Nd-Doped Microspinner at the Microscale.

Autor: Ortiz-Rivero E; Nanomaterials for Bioimaging Group, Departamento de Física de Materiales, Facultad de Ciencias & Instituto de materiales Nicolás Cabrera, Universidad Autónoma de Madrid, Madrid, 28049, Spain., González-Gómez CD; Nanoparticles Trapping Laboratory, Department of Applied Physics, Universidad de Granada, Granada, 18071, Spain.; Department of Applied Physics II, Universidad de Málaga, Málaga, 29071, Spain., Rica RA; Nanoparticles Trapping Laboratory, Department of Applied Physics, Universidad de Granada, Granada, 18071, Spain.; Research Unit 'Modeling Nature' (MNat), Universidad de Granada, Granada, 18071, Spain., Haro-González P; Nanomaterials for Bioimaging Group, Departamento de Física de Materiales, Facultad de Ciencias & Instituto de materiales Nicolás Cabrera, Universidad Autónoma de Madrid, Madrid, 28049, Spain.
Jazyk: angličtina
Zdroj: Small (Weinheim an der Bergstrasse, Germany) [Small] 2024 Aug; Vol. 20 (33), pp. e2308534. Date of Electronic Publication: 2024 Apr 04.
DOI: 10.1002/smll.202308534
Abstrakt: Thermal control at small scales is critical for studying temperature-dependent biological systems and microfluidic processes. Concerning this, optical trapping provides a contactless method to remotely study microsized heating sources. This work introduces a birefringent luminescent microparticle of NaLuF 4 :Nd 3+ as a local heater in a liquid system. When optically trapped with a circularly polarized laser beam, the microparticle rotates and heating is induced through multiphonon relaxation of the Nd 3+ ions. The temperature increment in the surrounding medium is investigated, reaching a maximum heating of ≈5 °C within a 30 µm radius around the static particle under 51 mW laser excitation at 790 nm. Surprisingly, this study reveals that the particle's rotation minimally affects the temperature distribution, contrary to the intuitive expectation of liquid stirring. The influence of the microparticle rotation on the reduction of heating transfer is analyzed. Numerical simulations confirm that the thermal distribution remains consistent regardless of spinning. Instead, the orientation-dependence of the luminescence process emerges as a key factor responsible for the reduction in heating. The anisotropy in particle absorption and the lag between the orientation of the particle and the laser polarization angle contribute to this effect. Therefore, caution must be exercised when employing spinning polarization-dependent luminescent particles for microscale thermal analysis using rotation dynamics.
(© 2024 The Authors. Small published by Wiley‐VCH GmbH.)
Databáze: MEDLINE
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