Heath Daniel J, Grant-Jacob James A, Feinaeugle Matthias, Mills Ben, Eason Robert W
Appl Opt. 2017 Aug 1;56(22):6398-6404. doi: 10.1364/AO.56.006398.
We present the use of digital micromirror devices as variable illumination masks for pitch-splitting multiple exposures to laser machine the surfaces of materials. Ultrafast laser pulses of length 150 fs and 800 nm central wavelength were used for the sequential machining of contiguous patterns on the surface of samples in order to build up complex structures with sub-diffraction limit features. Machined patterns of tens to hundreds of micrometers in lateral dimensions with feature separations as low as 270 nm were produced in electroless nickel on an optical setup diffraction limited to 727 nm, showing a reduction factor below the Abbe diffraction limit of ∼2.7×. This was compared to similar patterns in a photoresist optimized for two-photon absorption, which showed a reduction factor of only 2×, demonstrating that multiple exposures via ablation can produce a greater resolution enhancement than via two-photon polymerization.
我们展示了使用数字微镜器件作为可变照明掩膜，用于对材料表面进行激光加工的间距分割多重曝光。长度为150飞秒、中心波长为800纳米的超快激光脉冲用于在样品表面顺序加工连续图案，以构建具有亚衍射极限特征的复杂结构。在光学装置衍射极限为727纳米的情况下，在化学镀镍中制作出横向尺寸为几十到几百微米、特征间距低至270纳米的加工图案，显示出低于阿贝衍射极限约2.7倍的缩小因子。将其与优化用于双光子吸收的光刻胶中的类似图案进行比较，后者显示的缩小因子仅为2倍，这表明通过烧蚀进行多重曝光比通过双光子聚合能产生更大的分辨率增强。
