飞秒激光双光子微细结构的制备

基于双光子吸收引发的光聚合局限在紧密聚焦的焦点区域的原理,建立了飞秒激光三维微细加工系统;结合高斯光束的强度分布函数,推导了横向与轴向分辨率的表达式。在ORMOCER材料内实现了双光子光聚合,最高加工精度达到0.7μm。研究表明,加工线宽随功率增加而增加,随加工速度增加而减小;确定了波束腰为0.425μm,双光子吸收截面为2×10-54cm4.s。采用双光子光聚合技术,加工了齿宽5μm的实体微型齿轮,制备三维木堆型光子晶体结构,分辨率为1.1μm,杆间距和层间距均为5μm,实现了飞秒双光子光子晶体结构的制备。

Fabrication of Micro-Structures with Two-Photon Absorption Induced by Femtosecond Laser

Based on the theory that two photon absorption (TPA) induced by femtosecond laser was tightly confined in the focus, femtosecond laser three dimensional (3D) micro-fabrication system was set up; With the intensity distribution function of Gaussian beam, the lateral and axial resolution expressions were deduced. TPA photo-polymerization was achieved in ORMOCER resin, its resolution reached 0.7 μm. The line width was inversely proportional to the fabrication speed, and proportional to laser power. Beam waist of 0.425 μm and TPA cross-section of 2×10-54 cm4·s were obtained by simulation. With TPA photo-polymerization, micro-gear wheel with gear width of 5 μm has been manufactured. At last, 3D photonic crystal of wood-pile structure with four layers was fabricated, the space between the layers and sticks was both 5 μm, the resolution of the stick was 1.1 μm, it was the first photonic crystal (PhC) structure fabricated with TPA reported inland.