OPTOFLUIDIC TWEEZERS: MANIPULATION OF OIL DROPLETS WITH 10~5 GREATER FORCE THAN OPTICAL TWEEZERS

摘要

Optical droplet manipulation techniques typically generate small forces or require special substrates. This paper describes the concept of an optofluidic tweezer, where focused light energy at the interface of an oil droplet and its carrier fluid generates balanced thermocapillary flows which trap the droplet. The forces are attractive, and the large magnitudes (on the order of μN) enables the manipulation of a wide range of drop sizes. Using a 150mW, 405nm diode laser focused with a 10x objective, we demonstrate the trapping, manipulation, and merging of oil-in-water droplets ranging from 20-1000 μm at speeds of several mm/s.