Three-dimensional nanofabrication system for laser-driven micromachines

我们试图利用波导上产生的倏逝场的辐射力来驱动某些类型的微型机器。1)微动器辐射力分析及微动器设计，自行建立了微动器辐射力的计算方法。我们的方法基于边界元法（BEM）并扩展了Mie的理论。用该方法研究了能有效地将光能转化为微动器动能的微动器的形状和折射率。计算结果表明，当微动器的相对折射率约大于1.5时，利用光的共振效应可以提高能量传递效率。2)用紫外光固化树脂制备微动器为了制备不同类型的微动器，我们开发了一种三维微加工技术。在制造工艺中，利用近红外激光束通过双光子吸收工艺将三维体积上的一个点进行光聚合。通过扫描近红外激光束的聚焦点，可以制造出三维结构。我们的系统的分辨率已接近1倍。3)微动器驱动实验我们利用通道波导上产生的倏逝场驱动几种微动器。我们使用的微动器是介电和金属颗粒，直径为1-5微米。我们使用的光源是Nd: YLF激光器，其振荡波长为1047mum。在实验中，粒子被捕获在波导上产生的倏逝场范围内，并沿波导纵向运动。移动的速度和距离分别接近每秒10微秒和超过1厘米。

We tried to use the radiation force from the evanescent field, which is generated on the waveguide, for driving some kinds of micromachines.1) Analysis of the radiation force generated for micro-movers and design of micro-moversThe methods for calculating the radiation force were established by ourselves. Our methods base on boundary element method (BEM) and extended Mie's theory. The shape and refractive index of a micro-mover, which can transfer the energy of light to the kinetic energy of micro-mover efficiently, were examined by the methods. The calculation results showed that the efficiency of the energy transfer can be increased by using the resonance effect of light in case that the relative refractive-index of a micro-mover is greater than 1.5 approximately.2) Fabrication of a micro-mover with UV-cured resinWe developed a three-dimensional microfabrication technique in order to make some kinds of micro-movers. In the fabrication technique, a point in three-dimensional volume of UV-cured resin is photopolymerized through two-photon absorption process with a near-IR laser beam. A 3-D structure can be made by scanning the focused point of the near-IR laser beam. The resolution of our system have attained 1 mum nearly.3) Experiments on drive of micro-moversWe drove some kinds of micro-movers with the evanescent field generated on the channeled waveguide. The micro-movers we used are dielectric and metal particles whose diameter is 1-5mum. The light source we used is Nd : YLF laser whose oscillating wavelength is 1047mum. In the experiments, particles were trapped within the extent of the evanescent filed generated on the waveguide, and longitudinally ran along the waveguide. The velocity and the distance of the movement were near ten microins per second and over 1 cm, respectively.