Rostykus Manon, Rossi Mattia, Moser Christophe
Opt Lett. 2018 Apr 15;43(8):1654-1657. doi: 10.1364/OL.43.001654.
We report on a method to increase the spatial resolution in a compact lensless microscope. A compact side illumination is fabricated to illuminate the sample with a collimated beam by diffraction from a volume phase grating. The wavelength of a semi-conductor laser source (vertical-cavity surface-emitting laser) is tuned with the injection current to alter the illumination direction by wavelength selective diffraction from the volume phase grating. The angle tuning is such that several subpixel shifted digital inline holograms are obtained. The stack of holograms is then processed in a pixel super-resolution reconstruction algorithm. The amplitude of the sample is reconstructed with subpixel resolution over a large field of view (FOV). The technique is demonstrated on a 1951 USAF test target. A resolution of ∼2.76 , over a FOV of ∼28 , is demonstrated for a device of <2 height. The original pixel size was 5.2 μm demonstrating the subpixel resolution.
我们报道了一种提高紧凑型无透镜显微镜空间分辨率的方法。制作了一种紧凑型侧面照明装置，通过体相位光栅的衍射用准直光束照射样品。通过注入电流调节半导体激光源（垂直腔面发射激光器）的波长，以通过体相位光栅的波长选择性衍射改变照明方向。角度调节使得能够获得几个子像素移位的数字同轴全息图。然后，对全息图堆栈进行像素超分辨率重建算法处理。在大视场（FOV）上以子像素分辨率重建样品的幅度。该技术在1951年美国空军测试靶标上得到了验证。对于高度小于2的器件，在约28的视场上展示了约2.76的分辨率。原始像素尺寸为5.2μm，证明了子像素分辨率。
