An optical trap apparatus to study the thermophoretic phenomena

Abstract

The work is aimed at the development of the experimental device to study of the motion of different colloidal objects in the combined force field composed of the optical-trapping force originating in the light-intensity gradient and the thermophoretic force caused by the temperature gradient in aqueous solvents. Polystyrene microscopic beads of submicrometer diameters are used as a simple model of the optical tweezers calibration. The methods of generating temperature gradient are under development. A dual optical trap is used as a tool for the investigation of the thermophoretic force acting on the observed particles. Also, the generated optical trap's force constant is calculated by various methods, including Fast Fourier Transform, and the influence of differences in the sample environment and light intensity is compared. Results of these experiments should contribute to the theory of the optical trapping effect, so far not understood in detail, and should open a way for developing novel methods of the investigation of thermophoretic phenomena in a water environment.