At the transition from the macroscopic to the microscopic range fluids seem to change their physical behavior because of effects whose can be neglected at the macroscopic range. Here we are dealing with the scientific field of microfluidics. The focus of our team is dedicated to droplet based microfluidics. Thereby our aim is to develop new and efficient tools (chip sized labs or lab on chip devices) to manipulate fluids in a specific and precise manner at the one hand and at the other hand to enforce different novel and forward looking techniques for the purpose of all optical controlled droplets, suspended in microchannels or the surrounding air. This is to understand in the application of structured light fields to exert forces on droplets by nonlinear effects. In this way droplets can be stopped, levitated but also manipulated in their direction of movement at will.
Microchannels are directly manufactured in our labs by utilizing lithography methods. After applying these microstructures onto the surface of an electro optic material to create a lab on chip devices, droplets´ properties can be investigated subsequently by optical methods. Thereby our interests are focused on measurements of flow behavior, flow velocity as well as occurring forces. Our approaches are based in the dielectrophoretic effect, which is used for direct and specific optical control of droplets in microchannel environment and is applied as the electro optic tweezer. The photophoretic effect enables an effective manipulation of absorbing airborne droplets. Both concepts reveal a huge potential for further advanced applications.