RUI, OP: Space-Variant Polarization States of Light

光束（如激光束）的使用在现代技术的发展中具有变革性，从电话通信（其中信息被编码在通过光纤传播的光中）到激光手术（其中高光强度被递送到小区域的组织）。这些技术利用光的颜色或能量。光的另一个属性是它的偏振，这是肉眼不可见的，但可以间接看到，例如，通过某些类型的3D电影或偏振太阳镜的视觉效果。这项研究将涉及准备具有偏振的光束，这些光束在光束中从一点到另一点都不同，就像在图像中一样。这种偏振将被编码到单个光子（光的“粒子”）上。光子可以携带大量的信息，同时又是量子的，或者说是整体的。利用光和物质的量子方面的技术有可能将当前的通信技术升级到速度和容量大幅提高的技术。偏振也有望成为操纵手性分子或螺旋状分子的工具。这包括大多数有机分子，包括DNA（双螺旋）。 这项研究将测试最近的理论，这些理论预测光的偏振可用于将手性分子分离为从特定末端观察时顺时针或逆时针螺旋的分子（例如，DNA总是以一种方式螺旋，而不是另一种方式）。 这是合成药物的重要一步，因为以一种方式螺旋的分子可以治愈，而以另一种方式螺旋的分子可能会造成伤害。这项研究将涉及本科生，向他们介绍科学过程，同时在现代光子技术方面对他们进行培训。具有空间可变偏振的光的状态类似于纠缠量子态，因为两者都是不可分离的。因此，空变偏振态非常适合用于量子信息。它们通过以下方式为光子的量子态增加更高的维度：它们需要不可分离的偏振叠加（在二维中）和光的横向空间模式（原则上，增加无限数量的额外维度）。因此，空间模式为将量子信息编码到单个光子上的空间增加了更高的维度。我们已经开发了编码和解码这些状态的技术，由于它们的空间变化的偏振可以通过成像技术进行诊断。本研究将探讨光子对纠缠在偏振态和空间模中的空间，以及这些状态将编码的非局域空变偏振图像。与此同时，携带空间变偏振的强光束将被用于研究一种预测但尚未证实的新的光力，这种光力以这样一种方式影响手性分子，即它通过手性分离分子。也就是说，光产生场梯度，其施加对于右手和左手手性具有相反符号的力。这种新的力，基本上与光学活性有关，可能在复杂有机分子的化学合成中具有重要意义，其中需要将一种手性与另一种手性分离。

The use of beams of light, like laser beams, has been transformative in the development of modern technologies, from telephone communications where information is encoded in the light traveling through fibers, to laser surgery where high light intensity is delivered to small areas of tissue. These technologies exploit light's color or energy. Yet another property of light is its polarization, which is invisible to the unaided eye, but seen indirectly, for example, through the visual effects of some types of 3D movies or in polarizing sunglasses. This research will involve preparing light beams with polarization that varies from point to point across the beam, like in an image. This polarization will be encoded onto individual photons (the "particles" of light). Photons can carry a lot of information while at the same time being quantum, or whole. Technologies that harness the quantum aspects of light and matter have the potential to upgrade current communication technologies to ones with substantially increased speed and capacity. Polarization also holds promise as a tool to manipulate molecules that are chiral, or corkscrew-like. This encompasses most organic molecules, including DNA (the double helix). This research will test recent theories which predict that the polarization of light can be used to segregate chiral molecules into those that spiral clockwise or counterclockwise when viewed from a particular end (DNA always spirals one way but not the other, for example). This is an important step in the synthesis of medicines because molecules that spiral one way could cure while those that spiral the other way could cause harm. This research will involve undergraduates, introducing them to the scientific process while training them in modern photonic technologies. States of light that have spatially variable polarization are similar to entangled quantum states in that both are non-separable. Thus, space-variant-polarization states are well suited for use in quantum information. They add higher dimensions to the quantum states of photons in the following ways: they entail non-separable superpositions of polarization (in two dimensions) and transverse spatial modes of light (in principle, adding an infinite number of additional dimensions). Thus, spatial modes add a higher dimensionality to the space in which to encode quantum information onto single photons. We have developed techniques that encode and decode these states, which due to their space-variant polarization can be diagnosed by imaging techniques. This research will investigate the space of photon pairs entangled in polarization and spatial modes and the nonlocal space-variant polarization images that those states will encode. In parallel, intense beams carrying space-variant polarization will be used to investigate a predicted but yet unconfirmed new light force, which affects chiral molecules in such a way that it segregates the molecules by their handedness. That is, the light creates a field gradient that applies a force that is of opposite sign for right and left handed chiralities. This new force, fundamentally related to optical activity, could be of importance in the chemical synthesis of complex organic molecules, where it is desirable to separate one chirality from the other.