New Paradigms in Light-Based Measurements Using Unconventional Polarization States

偏振光（具有定向振动的光，其效果有时可以在旋转偏振太阳镜时的衰减变化中看到）无处不在-它在蓝天中，池塘的反射，自然和人造空气中颗粒的光散射，以及我们智能手机上的显示屏。偏振光的理解和使用是光科学和从医学到消费电子产品的应用的核心。例如，计算机信息革命的一些胜利是围绕制造技术建立的，这些技术要求几乎难以想象的测量精度-其中许多是基于光的，并以可以精确控制和测量的方式使用光的偏振。拟议的研究使用“非常规偏振态”的概念-一种特殊形式的光，其中偏振在激光束的宽度上变化-探索进行基于光的测量的全新方法。 结合一些特殊的光学设备，可以使用普通的相机在单个图像中创建偏振的视觉地图，这通常需要四个或更多图像的序列和伴随的算法。这些测量方法也将激发新的思路如何执行的同时测量的亚纳米工艺误差在微电子制造。多个测量所需的特性的超快激光脉冲或单个光子的偏振需要一个时间序列操作或明确的划分到不同的检测器端口的振幅。虽然每一种方法都取得了很好的成功，但需要真正扩展偏振测量，以便从每个测量的光子（在低光水平的情况下）或每个脉冲（在超快脉冲表征的情况下）中提取最大量的偏振信息。 由于该方法可扩展到在采样图像场上的偏振映射，因此可以扩展该概念以在单个图像中捕获角度分辨或频率分辨的偏振信息。该研究还将非常规偏振态的新物理学应用于现在著名的弱测量物理学，通过使用非常规偏振光在一次测量中测量两个或更多个物理量。这一概念将通过测量配备有液晶控制器的显微镜中的纳米尺度特征来进行测试，该液晶控制器定义了具有任意偏振、振幅和相位的聚焦光束散射测量的场。这项工作预计将影响物理学（通过引入新的测量方法），光学工程（特别是偏振工程和图像形成），生物医学光学（医学成像和光谱学），环境科学（通过使用偏振光散射气溶胶表征）和半导体检测的相关领域。

Polarized light (light with directional vibrations whose effects can sometimes be seen in changes in attenuation while rotating polarizing sunglasses) is everywhere--it is in the blue sky, the reflection from a pond, in light scattering from natural and manmade airborne particles, and in the display screens on our smartphones. The understanding and use of polarized light is central to both the science of light and to applications ranging from medicine to consumer electronics. For example, some of the triumphs of the computer information revolution have been built around manufacturing technologies that require almost unimaginable precision in measurements--many of which are light-based and use the polarization of light in ways that can be precisely controlled and measured. The proposed research uses the concept of an "unconventional polarization state" - a special form of light in which the polarization varies across the width of a laser beam - to explore fundamentally new ways of carrying out light-based measurements. In conjunction with some special optical devices, it is possible to use an ordinary camera to create a visual map of the polarization in a single image, something that ordinarily requires a sequence of four or more images and accompanying algorithms. These measurement methods will also spur new ways of thinking about how to execute the simultaneous measurement of sub-nanometer process errors in microelectronics manufacturing.The multiple measurements required to characterize the polarization of an ultrafast laser pulse or individual photon require either a time-sequential operation or explicit division of the amplitude into different detector ports. While each of these has been used to good success, there is a need to truly extend polarization measurements in a way that the maximum amount of polarization information is extracted from each measured photon (in the case of low light levels) or each pulse (in the case of ultrafast pulse characterization). Because the method is extendable to the mapping of polarization over a sampled image field, it is possible to extend the concept to capture either angle- or frequency-resolved polarization information in a single image. The investigation also applies the new physics of unconventional polarization states to the now-famous physics of weak measurements by using unconventionally polarized light to measure two or more physical quantities in a single measurement. This concept will be tested by measuring nanoscale features in a microscope equipped with a liquid crystal controller that defines a field with arbitrary polarization, amplitude, and phase for focused beam scatterometry. The work is expected to impact allied areas of physics (through the introduction of new measurement methods), optical engineering (specifically, polarization engineering and image formation), biomedical optics (in medical imaging and spectroscopy), environmental science (through the use of polarimetric light scattering for aerosol characterization), and semiconductor inspection.