[11p-C310-1~10] 3.1 Basic optics and frontier of optics

4:00 PM - 4:15 PM JST(7:00 AM - 7:15 AM UTC)English Presentation

[11p-C310-8] Chemically Selective Mid-Infrared Optical Tweezers for Polymer Microparticle Manipulation

〇(P)Adem Mohamed DAHI¹, Yuto Shimizu¹, Takao Fuji¹, Tetsuhiro Kudo¹ (1.Toyota Tech. Inst.)

Keywords:

Mid-infrared,Polymer microparticles,Optical trapping

Optical tweezers enable contactless manipulation of micro and nano objects, but most implementations operate in the visible or near infrared range, where trapping mainly depends on size, morphology, and refractive index contrast. This limits the selective manipulation of particles that are geometrically similar but chemically different. Here, we demonstrate mid infrared optical tweezers for chemically selective manipulation of polymer microparticles. Using a tunable continuous wave quantum cascade laser in the carbonyl stretching region, we compare PMMA, PLA, and PET particles with similar optical appearance but distinct infrared signatures. By tuning the excitation between 1680 and 1760 cm-1, we observe material dependent trapping responses: PMMA and PLA switch from stable confinement to expulsion at different wavenumbers, whereas PET remains trapped with weaker modulation. These results establish MIR optical tweezers as a label free platform for chemically selective optical manipulation.