OBSERVATION AND SIMULATION OF OPTICAL DIFFRACTION PATTERN OF A ROTATING MICROGEAR

摘要

The emerging field of micro fluidics is challenged with a desire to pump, move and mix minute amounts of fluid. Such micro devices are operated by means of light matter interaction, namely they can be driven through utilizing birefringence and the polarization of the light as well as the reflection and refraction of light. The latter one enables micro motors to be operated in a tangential setup where the rotors are on axis with an optical waveguide. This has the advantage that the complexity of driving such a device in a lab on a chip configuration is reduced by delivering the driving light by means of a waveguide or fiber optics. In this publication we study a micro motor being driven by a fiber optically delivered light beam. We present experimentally and theoretically how light is getting diffracted when in interaction with the rotors of a turning micro motor. By utilizing the two photon signal from a fluorescein dye being excited by a pulsed femtosecond Laser which was used to drive the motor. Additionally the rotation rate is investigated in dependence of the light field parameters.