Photonic nanowires for optical sensing and signal processing

纳米技术的发展支撑了许多科学和技术领域。在1-100纳米的长度尺度上精确构建表面、材料和器件的能力为ICT、生物医学传感和环境监测领域开辟了新的器件和系统的可能性。本提案中概述的研究计划包括基于电子束光刻的纳米制造工艺的使用及其在开发高折射率对比度波导结构方面的应用。在接下来的五年里，学生项目将集中在三个领域，a)电子束光刻和工艺开发，b)用于波长转换的光子线和3)用于光学传感应用的光子线。2009年，我们正式启用了新的电子束光刻系统，它允许在大范围内定义低至10纳米的特征。这种工具的高光束电流和低拼接误差允许对各种结构进行图案化，包括用于生物、传感和光子学的纳米结构表面。基本制造工艺的质量决定了最终波导、谐振器和光子晶体的质量。我们计划优化电子束图案化工艺，以减少最小特征尺寸，改善写入时间，并减少导致光子波导结构中高散射损失的边缘粗糙度。利用高折射率对比度光波导实现波长转换有很多优点。较小的纤芯尺寸增加了局域强度，波导结构可用于色散工程波导以实现相位匹配，而谐振器可进一步提高转换效率。在纳米线波导中设计色散和场分布的能力在光学传感中也有应用。通过使波导变窄、结合光子晶体或缺陷状态，可以控制光场与传感材料的重叠。本申请中概述的研究计划将为获得纳米制造、集成光学电路设计和光学测试技能的学生提供理想的培训场所。

Developments in nanotechnology underpin many areas of science and technology. The ability of accurately structure surfaces, materials and devices on the length scale of 1 - 100 nm opens up new device and system possibilities in the areas of ICT, biomedical sensing and environmental monitoring. The program of research outlined in this proposal covers the use of nanofabrication processes based around electron beam lithography and their application to develop high refractive index contrast waveguide structures. There are three areas where student projects will be focused over the next five years, a) electron beam lithography and process development b) photonic wires for wavelength conversion and 3) Photonic wires for optical sensing applications. In 2009 we officially opened our new electron beam lithography system, which allows features down to 10 nm to be defined across large areas. The high beam current, and low stitching errors possible with this tool allow a wide range of structures to be patterned, including nano-structured surfaces for biology, sensing and photonics. The quality of the underlying fabrication processes dictates the quality of the final waveguides, resonators and photonic crystals. We plan to optimize the ebeam patterning process to reduce the minimum feature size, improve writing time and reduce edge roughness that leads to high scattering losses in photonic waveguide structures. The use of high refractive index contrast waveguides to implement wavelength conversion has many advantages. The small core size increases the local intensity, the waveguide structure can be used to dispersion engineering the waveguide to enable phase matching and resonators can be used to further enhance the conversion efficiency. The ability to engineer the dispersion and field profile in a nanowire waveguide also has applications in optical sensing. By narrowing the waveguide, incorporating a photonic crystal, or defect state it is possible to control the overlap of the optical field with the sensing material. The program of research outlined in this application will provide an ideal training ground for students who will gain skills in nanofabrication, integrated optical circuit design and optical testing.