LASER,OPTO MICROENGINE ROTATED BY QUANTAM EFFECTS

我们提出了一个光微引擎作为微执行器提供的光能。光微发动机利用分子气体动力学效应旋转。由于转子表面的摩擦损失在微观尺度上影响着转子的转动力矩，因此减小摩擦损失具有重要意义。然后我们注意到将单光束梯度光阱应用于光微引擎。本文讨论了在射线光学范围内，单光束梯度辐射压力作用于微米级介质球所产生的激光陷阱力的计算问题。光辐射压力由入射光线角度和相对折射率来计算。结果表明，要获得良好的陷波效果，需要高数值孔径（N.A.）objective.利用激光捕集实验装置实现了纯水中直径为5 μ m的微小颗粒的激光捕集，揭示了气体分子量对激光光微发动机性能的影响。氦、氩和氙被用作操作光微引擎的环境气体。随着气体分子量的减小，发动机的最大静转矩增大。采用直接模拟蒙特卡罗方法对气体分子在光微发动机周围的运动进行了数值模拟。DSMC方法的数值结果表明，发动机叶片前后表面间的压力差与气体分子量有关

We propose a opto-microengine as a micro-actuator supplied optical energy. The opto-microengine is rotated by the molecular gas dynamics effects. As the friction loss on the surface of the rotor effects the torque of rotation at the size-order of microscopic length, it is important to decrease the friction loss. Then we notice to apply single-beam gradient optical trapping to the opto-microengine. In the present research project the calculation of the forces for laser trap by single-beam gradient radiation pressure on micron-sized dielectric spheres in the regime of the ray optics are discussed. The optical radiation pressure is evaluated by incident ray angle and a relative index of refraction. It is shown that good trapping requires high convergence beams produced by a high numerical aperture (N.A.) objective. By using the trapping experimental facilities it is realized that the fine particles with 5 micro-meter diameter in pure water are trapped by the laser beam.In this rsearch project the effects of gas molecular weights on laser opto microengine performance are revealed. Helium, argon, and zenon are used as an environmental gas for operating of the opto microengines. With decreasing the gas molecular weights, the maximum static torques of the engines increase. Gas molecular motions around the opto-microengines are numerically simulated by the Direct Simulation Monte Carlo method. The numerical results by the DSMC method show that the pressue differemces between forward and backward surfaces of the engine blades are dependent on the gas molecular weights