Presentation Information
[8p-A31-12]Thermophoretic microparticle manipulation in an annular optical beam
〇(M2)Zepaniah Potutan1, Khate Cheryl Bayer1, Romie Seth Florida1, Mark Nolan Confesor1 (1.MSU-IIT)
Keywords:
optical tweezers,optics,thermophoresis
Achieving stable particle confinement is a critical challenge in microscale optical manipulation; optical tweezers are limited by weak radiation pressure and photothermal diffusion, while conventional laser-induced thermophoresis creates repulsive thermal barriers . In this work, we present a thermophoretic approach, using holographic optical tweezers to project an annular beam onto a chromium-coated substrate. This configuration inverts the standard thermal gradient, forming a localized potential well that stably confines ~2.29 μm thermophobic polystyrene particles within its cooler center while simultaneously repelling other particles from the trap. Tracked particle dynamics demonstrate strong agreement with 2D simulations coupling steady-state heat transfer and stochastic overdamped Langevin dynamics. By validating these empirical concentration profiles and trajectories, our results demonstrate a reliable method to simultaneously control, assemble, and sort microparticles.