4PI Two-photon Lithography for Isotropic 3D Nanostructure Fabrication

光学光刻是一种利用光在材料中定义特定图案的过程。标准光学光刻能够在两个维度上对材料进行图案化，并且可能的特征尺寸随光的波长而变化。正是对这一过程和相关技术的研究一直是技术革命的主要驱动力之一，部分原因是计算机硬盘驱动器中的面密度降低和处理器能力每18个月翻一番(摩尔定律)。随着我们在21世纪的进步，纳米尺度上的3D架构很可能在为未来的数据处理和存储技术开发先进材料方面变得重要。双光子光刻是一种最近被商业化的3D制造方法，它对科学产生了巨大的影响，允许在200纳米的水平和500 nm的垂直长度尺度上制造定制的3D几何图形。商用双光子光刻技术使多个领域的科学家能够制造出几个-100纳米尺度的3D系统，从而实现了用于靶向药物输送、生物支架以及一系列光子和机械超材料的游泳微型机器人。双光子光刻的一个重大挫折是横向和垂直分辨率的不对称，这限制了可以实现的绝对尺寸和几何类型。在这项提议中，我们将利用我们在非线性显微镜领域的世界领先专业知识来改进商业双光子光刻系统，并获得更高的分辨率。我们将利用已经显著提高荧光显微镜分辨率的技术，以实现100 nm的各向同性分辨率。新建成的系统将被我们的团队用来制造两种类型的3D纳米级磁性材料，在几何尺寸和长度尺度上，这是使用其他制造方法难以实现的。我们在这方面的工作将为下一代三维存储技术，如磁道存储技术铺平道路，并帮助我们理解新型磁性材料中的磁电荷输运。此外，我们将与再生医学和光子学领域的项目合作伙伴合作，以实现一些新型的3D纳米结构材料。首先，我们将与干细胞研究人员合作，制造用于干细胞分化实验的人造组织。我们在这里的工作将提供一个引人入胜的洞察纳米级地形在干细胞分化中的作用，并最终可能在组织/器官生长中应用。其次，我们将与研究光子晶体的学者合作--光子晶体是一种人造材料，能够在一定的光谱范围内阻挡电磁辐射。到目前为止，已经制造的大多数3D光子晶体能够衰减光谱可见范围外的电磁波，限制了其在光电子学中的应用。我们的工作将允许制造和测量可用于可见光和红外光的光子晶体。这项工作可能为下一代可用于电信行业的三维光学电路铺平道路。总体而言，该项目将建造一种国际独一无二的仪器，并利用它来制造一系列先进材料。这将使英国在3D光刻技术以及相关的生物医学、磁性和光子材料方面处于领先地位，这些材料将使用我们新建造的仪器实现。

Optical lithography is a process that utilises light to define a specific pattern within a material. Standard optical lithography is capable of patterning materials in two dimensions and the possible feature size scales with the wavelength of the light. It is research into this process and associated techniques that has been one of the main drivers of the technological revolution, is partly responsible for the reduction of areal density within computer hard drives and the doubling of processor power every 18 months (Moore's Law).As we progress through the 21st century it is likely that 3D architectures on the nanoscale will become important in developing advanced materials for future data processing and storage technologies. Two-photon lithography is a 3D fabrication methodology that has recently been commercialised and is having a huge impact upon science, allowing the fabrication of bespoke 3D geometries on a length-scale of 200nm horizontally and 500nm vertically. Commercial two-photon lithography has made the fabrication of 3D systems on the several-100nm scale accessible to scientists in a variety of fields allowing the realisation of swimming micro-robots for targeted drug delivery, bioscaffolds and a range of photonic and mechanical metamaterials. A significant setback with two-photon lithography is the asymmetry in the lateral and vertical resolution, which limits both the absolute size and the type of geometry that can be realised. In this proposal, we are going to utilise our world-leading expertise in non-linear microscopy to modify a commercial two-photon lithography system and obtain enhanced resolution. We will utilise techniques that have already significantly improved the resolution in fluorescence microscopy in order to achieve a 100nm isotropic resolution. The newly built system will be used by our team to fabricate two types of 3D nanoscale magnetic materials, in geometries and on length-scales that are difficult to achieve using other fabrication methodologies. Our work in this area will pave the way for next generation 3D memory technolgies such as magnetic racetrack memory and help us to understand magnetic charge transport in novel magnetic materials. In addition, we will be working with project partners in the regenerative medicine and photonics communities in order to realise a number of novel 3D nanostructured materials. Firstly, we will work with stem cell researchers in order to fabricate artificial tissues that will be used in stem cell differentiation experiments. Our work here will provide a fascinating insight into the role of nanoscale topography upon stem cell differentiation and may eventually have applications in tissue/organ growth. Secondly, we will work with academics studying photonic crystals - artificial materials that are capable of blocking electromagnetic radiation within a certain range of the spectrum. The majority of 3D photonic crystals that have been made to date are capable of attenuating electromagnetic waves that are outside the visible range of the spectrum, limiting applications in optoelectronics. Our work here will allow the fabrication and measurement of photonic crystals that can be used with visible and infra-red light. This work may pave the way to next generation three-dimensional optical circuits that can be utilised by telecommunication industries.Overall, this project will build an internationally unique instrument and utilise it to fabricate a range of advanced materials. This will put the U.K. at the forefront of 3D lithography technologies and the associated biomedical, magnetic and photonic materials that will be realised using our newly built instrument.