Advantages of Holographic Optical Tweezers

摘要

In the last decade optical tweezers became an important tool in microbiology. However the setup becomes very complex if more than one trap needs to be moved. Holographic tweezers offer a very simple and cost efficient way of manipulating several traps independently in all three dimensions with an accuracy of less than 100 nm. No mechanically moving parts are used therefore making them less vulnerable to vibration. They use computer-generated holograms (CGHs) written into a spatial light modulator (SLM) to control the position of each trap in space and to manipulate their shape. The ability to change the shape of the optical trap makes it possible to adapt the light field to a specific particle shape or in the case of force measurements to adjust the trapping potential. Furthermore the SLM can be used to correct for aberrations within the optical setup.