Optical Tweezers

We are interested in developing direct imaging techniques to track the dynamics of trapped particles in real-time and realize techniques for sensitive measurements of physical properties.

Key Papers

Time domain metrology with optical tweezers, G. Carlse, K. Borsos, T. Vacheresse, A. Pouliot, E. Ramos, J. Randhawa, C. Walsh, and A. Kumarakrishnan, Proc. SPIE 12447, Quantum Sensing, Imaging, and Precision Metrology, 124470G (2023) (5 pages)

Technique for Rapid Mass Determination of Airborne Microparticles Based on Release and Recapture from an Optical Dipole Force Trap, G. Carlse, K. B. Borsos, H. C. Beica, T. Vacheresse, A. Pouliot, J. Perez-Garcia, A. Vorozcovs, B. Barron, S. Jackson, L. Marmet and A. Kumarakrishnan, Physical Review Applied 14, 024017 (2020)

Schematic diagram of the experimental setup. The focal lengths of the beam shaping lenses are l₁ ~ 45 cm and l₂ ~ 30 cm. The mirrors in between the acoustic-optic modulator (AOM) and the 10x objective (MO) act as a periscope such that the beam entering the MO is directed downward along the vertical direction. Here, TA represents the tapered amplifier, λ/2 represents a half-wave plate, PBS represents a polarizing cube beam splitter, PM represents a power meter, BB represents a beam block, TPE represents the trapped particle enclosure, VTL represents the variable telescope, and CMOS represents the camera.

Shows the fall distance as a function of drop time.

Shows the restoration trajectories along the vertical axis of the trapping beam for a representative set of drop times.