Department of Physics, University of York, Heslington, York, UK.
Opt Lett. 2013 Sep 1;38(17):3410-3. doi: 10.1364/OL.38.003410.
We demonstrate high aperture (up to NA~0.64) three-dimensional focusing in free space based on wavefront-engineered diffraction gratings. The grating lens' optical response is tailored by spatially varying the grating ridge and groove width in two dimensions to achieve focal lengths of order 100 μm that are crucial for micro-optical applications. The phase profile of the lens includes multiple 2π phase jumps and was obtained by applying an algorithm for finding the optimal path for both phase and amplitude. Experimental measurements reveal a lateral spot size of 5 μm that is close to the size of a corresponding Airy disk.
我们展示了基于波前工程衍射光栅的高孔径（高达 NA0.64）自由空间三维聚焦。通过在两个维度上空间变化光栅脊和槽的宽度来调整光栅透镜的光学响应，以实现对微光学应用至关重要的(order100μm) 焦距。透镜的相位分布包括多个 2π 相位跃变，并且通过应用一种用于找到相位和幅度的最优路径的算法获得。实验测量显示，横向光斑尺寸为 5μm，接近相应的艾里斑的尺寸。
