A novel optical tweezers system

摘要

Optical tweezers, first developed by Askin et al, is an increasingly important technique for trapping and moving matter at length scale ranging from nanometers to millimeters. In recent years, the improvement of tweezers apparatus emphasizes two aspects: one is to make the traps more practical and the other is to manipulate micro-particles more conveniently. The article brought forward one kind of novel implement which can provide optical traps of arbitrarily forms and can control the traps at will. The optical tweezers is based on real-time computer generated holography. The paper described the implementation of the technique in detail and gave experimental results. The system is a dynamic holographic optical tweezers based on a computer controlled TFT-LCD. By using FFT, we can make desired types of traps which can be draw up with mouse on computer displayer into dynamic holograms. The hologram reconstruction is based on TFT-LCD. While laser illuminates on TFT-LCD and passes through the next optical system, we get the traps we need and it can be controlled freely. The tweezers system can form multi-traps, hollow traps, and many other forms of traps. It is more convenient and rapid to control the trap's position in our tweezers system, and the cost of the system is reduced. This provides new means for the development of optical tweezers.