Replacement Laser for Holographic Fabrication of Photonic Crystals

这项拨款提案旨在使我们能够购买激光系统的替代品。激光在过去一直很麻烦，而且越来越糟——它已经无法使用两个月了，在这段时间里，制造商还没有提出如何恢复使用的建议。激光对我们的研究至关重要——没有替代品，我们就无法继续这个由EPSRC资助的项目，该项目如下所述。光子晶体是具有规则、重复、波长尺度微观结构的光学材料。光子晶体是“光学半导体”，其特性使其独特地适用于制造光子集成电路。它们的特性是一个“光子带隙”——一个被禁止的频率范围，在这个范围内，这种结构就像一个光学绝缘体。带有结构缺陷的“掺杂”引入了局域电磁模式，可用于制造集成光学器件的组件，如波导和微腔。在光子晶体中可能实现的高水平的光隔离意味着基于光子晶体的集成光电路有望接近电子设备的集成密度，这一发展将彻底改变电信信号的处理。在牛津大学物理系和化学系的合作中，我们开发了一种制造光子晶体的全新方法。我们使用三维全息激光干涉图案在光刻胶厚膜上创建必要的亚波长微结构。然后，我们使用专用的共聚焦显微镜来修改其结构，以在其内部创建波导等结构。这种技术本身便宜且快速，它提供了独特的灵活访问范围广泛的3D光子晶体现象，并且可以很容易地扩大到商业生产。在这个提案中，我们的目标是创建3D光子晶体，它适用于光纤通信中使用的波长范围。我们还致力于在三维光子晶体中创建工程结构缺陷，并研究缺陷结构与掺杂晶体光学特性之间的关系，这是迈向微米级光学器件三维集成的重要一步。

This grant proposal is intended to enable us to buy a replacement for a laser system. The laser has been troublesome in the past and is getting worse - it has been unusable for two months, and in that time the manufacturer has not been able to suggest how it might be returned to use. The laser is essential to our research - without a replacement we cannot continue with a project already funded by EPSRC which is described below.Photonic crystals are optical materials with regular, repeated, wavelength-scale microstructure. Photonic crystals are 'optical semiconductors' whose properties make them uniquely suitable for the fabrication of photonic integrated circuits. Their characteristic property is a 'photonic band gap' - a forbidden frequency range within which the structure acts as an optical insulator. 'Doping' with structural defects introduces localized electromagnetic modes which may be engineered to create the components of integrated optical devices, such as waveguides and microcavities. The high level of optical isolation that may be achieved within a photonic crystal means that photonic crystal-based integrated optical circuits promise to approach the density of integration of electronic devices, a development which will revolutionize the handling of telecommunications signals. In a collaboration between the Physics and Chemistry Departments at Oxford University we have developed a completely new way to make photonic crystals. We use a three-dimensional holographic laser interference pattern to create the necessary sub-wavelength microstructure in a thick film of photoresist. We then use a purpose-built confocal microscope to modify the structure to create waveguide etc. structures within it. This technique is inherently cheap and quick / it gives uniquely flexible access to a wide range of 3D photonic crystal phenomena and could be readily scaled up to commercial manufacture. In this proposal we aim to create 3D photonic crystals which are suitable for use in the range of wavelengths used in optical fibre telecommunications. We also aim to create engineered structural defects within 3D photonic crystals and to investigate the relationship between the structure of the defects and the optical properties of the 'doped' crystal as an important step towards three-dimensional integration of micrometer-scale optical devices.