Design Of Dual Trap Optical Tweezers With A Single Light Source And Trap Anaylse And Simulation Reaserch

Laser Biography is a multi-discipline crossed new area, and the optical tweezers technology based on microbeam laser is an effective tool in the research of life science and bioengineering. The gradient force formed by a strongly focused laser beam can capture the dielectric neutral particles on its focus point, the size of the particles ranges from nm to μm. Optical tweezers can be used to manipulate biological animate specimens without physical contact and invasion. It has now become one of the research hot spot of new method and new instrument in biophysics.In this thesis, the theory of optical tweezers based on microbeam laser is described. The quantitative calculation and simulation results and analysis of optical trapping force is given. The optical tweezers instrument with one optical trap and two optical traps is designed respectively. The stability and effective of the system are also studied.By using the RO model, which is based on the theory of geometric optics, the optical trapping force on the microsphere particles in the Mie scattering field is calculated quantitatively. The simulation results under given parameters are described. According to the simulation results, the relations between the optical trapping force and the main parameters of the system, including focus spot radius, the relative refractive index, the laser wave-length and power and so on, is discussed. Effects of spherical aberration caused by the refractive mismatch between objective oil and medium water on optical trapping force is calculated quantitatively and also analyzed. The transverse trapping force can be increased effectively by modifying laser profile, while the longitudinal stability of the system is still assured. It will improve the steering speed of optical trap. For the particles in the Rayleigh scattering field, the optical trapping force calculation result based on the theory of electromagnetic field is also described.In the apparatus design aspect, at first we design an optical tweezers instrument with one optical trap. On this basis, then we design an optical tweezers instrument with two optical traps using a single light. We described the stability and effective of this system of each optical trap in detail when steering the optical trap in three dimension independently. This paper is a preparatory job in terms of theory and technology for constructing a fully steerable dual optical trap tweezers. It is of importance reference value to optical tweezers research in instrument design and its wider application in life science and biography technology.