Liquid viscosity measurement based on current-modulated single-fiber optical tweezers

This paper proposes a solution viscosity measurement method based on single-fiber optical tweezers. Polystyrene (PS) particles were captured using a tapered fiber probe and used as a sensing element. The PS particles were manipulated to undergo axial reciprocating motion in the solution by injecting a current-modulated 980 nm laser into the tapered fiber probe. The solution viscosities were inverted using the distances traveled by the PS particles in solutions of different viscosities. The experimental results show that this method can realize the viscosity measurement of the background solution viscosity from 1 mPa · s to 4.1 mPa · s, which provides a new method in the field of solution viscosity measurement.