Adaptive optics for three-dimensional microscopy and photonic engineering

光是一种多功能的工具，用于微观尺度上的成像和工程。光学显微镜使用聚焦光，因此我们可以以高分辨率观察样品。这些显微镜被广泛用于生命科学，允许可视化的细胞结构和亚细胞过程。然而，光学显微镜的分辨率往往受到它成像的标本的存在的不利影响。样品的光学性质的变化引入光学畸变，称为像差，其损害图像质量。这是一个特殊的问题，当成像深入到厚标本，如皮肤或脑组织。最终，畸变限制了显微镜可以观察到的样本量，深度通常限于表面附近的几个细胞层。这是一个严重的限制，如果你想观察细胞及其过程中的自然环境，而不是在显微镜载玻片上。我正在开发一种显微镜，它可以消除有问题的像差，并能在标本深处实现高分辨率成像。聚焦光还有其他不太为人所知的用途。它可用于引发化学反应，产生聚合物或金属构件，用于亚微米级的制造。这些块的尺寸小到几十纳米，可以以逐块的方式构建成结构。或者，可以使用高强度的聚焦激光将较大的材料块雕刻成形状。这些光学制造方法显示出在纳米技术设备的制造中使用的潜力。当制造这样的装置时，激光必须通过预制结构的部分聚焦。结构的总体尺寸和复杂性越大，像差的影响越使制造系统的精度降级。传统的光学系统主要由静态元件组成，例如用于聚焦的透镜、用于反射和扫描的反射镜以及用于分离不同波长的棱镜。然而，在我使用的系统中，像差是不断变化的。因此，它们需要一种自适应的校正方法，其中像差被动态补偿。这些自适应光学技术最初是为天文和军事目的而开发的，用于稳定和消除恒星和卫星的望远镜图像模糊。这样的图像受到地球大气层中湍流引入的像差的影响。这一现象最明显的表现是肉眼所见的星星闪烁。最近的技术发展，如紧凑和负担得起的可变形反射镜，用于补偿光学失真，意味着这项技术现在正在开发更多的脚踏实地的原因。我将与日本和澳大利亚的研究人员一起开发自适应光学制造系统，该系统将能够以比以前更高的精度制造复杂的微米级结构。与牛津大学的生物学家一起，我将使用自适应光学来提高显微镜在厚标本中成像的能力。这将使生物学家能够更多地了解细胞内发生的过程和生物体的发育。像差校正技术也将用于其他领域，如医学成像，光通信和天文学。

Light is a versatile tool for imaging and engineering on microscopic scales. Optical microscopes use focused light so that we can view specimens with high resolution. These microscopes are widely used in the life sciences to permit the visualisation of cellular structures and sub-cellular processes. However, the resolution of an optical microscope is often adversely affected by the very presence of the specimen it images. Variations in the optical properties of the specimen introduce optical distortions, known as aberrations, that compromise image quality. This is a particular problem when imaging deep into thick specimens such as skin or brain tissue. Ultimately, the aberrations restrict the amount of the specimen that can be observed by the microscope, the depth often being limited to a few cellular layers near the surface. This is a serious limitation if one wants to observe cells and their processes in their natural environment, rather than on a microscope slide. I am developing microscopes that will remove the problematic aberrations and enable high resolution imaging deep in specimens.Focused light also has other less well-known uses. It can be used to initiate chemical reactions that create polymer or metal building blocks for fabrication on the sub-micrometre scale. These blocks, with sizes as small as a few tens of nanometers, can be built into structures in a block-by-block fashion. Alternatively, larger blocks of material can be sculpted into shape using the high intensities of focused lasers. These optical methods of fabrication show potential for use in the manufacture of nanotechnological devices. When manufacturing such devices, the laser must be focused through parts of the pre-fabricated structure. The greater the overall size and complexity of the structures, the more the effects of aberrations degrade the precision of the fabrication system. My research centres on the use of advanced techniques to measure and correct such distortions, restoring the accuracy of these optical systems.Traditional optical systems consist mainly of static elements, e.g. lenses for focusing, mirrors for reflecting and scanning, and prisms for separating different wavelengths. However, in the systems I use the aberrations are changing constantly. Therefore they require an adaptive method of correction in which the aberrations are dynamically compensated. These adaptive optics techniques were originally developed for astronomical and military purposes, for stabilising and de-blurring telescope images of stars and satellites. Such images are affected by the aberrations introduced by turbulence in the Earth's atmosphere. The most obvious manifestation of this is the twinkling of stars seen by the naked eye. Recent technological developments, such as compact and affordable deformable mirrors for compensating the optical distortions, mean that this technology is now being developed for more down-to-Earth reasons. This has opened up the possibility of using adaptive optics in smaller scale applications.In conjunction with researchers in Japan and Australia, I will develop adaptive optical fabrication systems that will be able to produce complex micrometre-scale structures with greater accuracy than was previously possible. With biologists in the University of Oxford, I will use adaptive optics to increase the capabilities of microscopes in imaging deep into thick specimens. This will enable biologists to learn more about the processes that occur within cells and the development of organisms. The aberration correction technology will also have use in other areas such as medical imaging, optical communications and astronomy.