Beam manipulation and force estimation in a dynamic holographic optical tweezers

In this paper we discuss the implementation of a dynamic holographic optical tweezers using a liquid crystal spatial light modulator (LCSLM) assembly. The LCSLM assembly can realize reconfigurable binary holograms and generate beams with user defined phase profiles. Depending on the nature of the liquid crystal molecule used, the LCSLM can provide a hologram update rate of 60 Hz to at least 1440 Hz. Thus the LCSLM can provide a trapping beam whose phase profile can be updated in real time. Such an optical tweezers therefore can be termed as dynamic holographic optical tweezers. In this paper we will show how the LCSLM assembly can facilitate various beam manipulation mechanisms which in turn can be utilized to estimate the optical force acting on the microscopic particle being trapped.