Pixel level optical-transfer-function design based on the surface-wave-interferometry aperture.

The design of optical transfer function (OTF) is of significant importance for optical information processing in various imaging and vision systems. Typically, OTF design relies on sophisticated bulk optical arrangement in the light path of the optical systems. In this letter, we demonstrate a surface-wave-interferometry aperture (SWIA) that can be directly incorporated onto optical sensors to accomplish OTF design on the pixel level. The whole aperture design is based on the bull’s eye structure. It composes of a central hole (diameter of 300 nm) and periodic groove (period of 560 nm) on a 340 nm thick gold layer. We show, with both simulation and experiment, that different types of optical transfer functions (notch, highpass and lowpass filter) can be achieved by manipulating the interference between the direct transmission of the central hole and the surface wave (SW) component induced from the periodic groove. Pixel level OTF design provides a low-cost, ultra robust, highly compact method for numerous applications such as optofluidic microscopy, wavefront detection, darkfield imaging, and computational photography.

光学传递函数（OTF）的设计对于各种成像和视觉系统中的光学信息处理至关重要。通常，OTF设计依赖于光学系统光路中复杂的体光学布置。在本文中，我们展示了一种表面波干涉孔径（SWIA），它可以直接集成到光学传感器上，以在像素层面实现OTF设计。整个孔径设计基于牛眼结构。它由一个在340纳米厚的金层上的中心孔（直径300纳米）和周期性凹槽（周期560纳米）组成。我们通过模拟和实验表明，通过控制中心孔的直接透射与周期性凹槽诱导的表面波（SW）分量之间的干涉，可以实现不同类型的光学传递函数（陷波、高通和低通滤波器）。像素层面的OTF设计为众多应用提供了一种低成本、超稳健、高度紧凑的方法，例如光流体显微镜、波前检测、暗场成像和计算摄影。