arXivDaily arXiv每日学术速递 周一至周五更新
arXiv 0708.3206physics.acc-phphysics.optics
收藏

光子晶体laser驱动的加速器结构

Photonic crystal laser-driven accelerator structures

Benjamin M. Cowan

摘要:

激光驱动的加速技术有望显著提高加速梯度。然而,将真空中基于结构的加速的传统过程缩小到光学波长需要基本上不同种类的结构。我们要求光波导(1)由电介质材料构成,(2)具有波长量级的横向尺寸,以及(3)支持真空中具有光速相速度的模式。光子晶体--其电磁特性具有空间周期性的结构--可以满足这些要求。我们讨论了模拟的光子晶体加速器结构,并描述了它们的特性。我们从一类二维结构开始,用来说明设计考虑和权衡。然后,我们提出了一个三维结构,并描述其性能的加速梯度和效率。我们讨论粒子束动力学在这种结构中,展示了一种方法,用于保持光束局限于波导。我们还讨论了材料和制造的考虑。由于加速梯度受到结构的光学损伤的限制,因此电介质的损伤阈值是一个关键参数。我们实验测量硅的皮秒脉冲在红外线的损伤阈值,并确定我们的结构是能够维持在1550 nm的300 MV/m的加速梯度。最后,我们讨论了制造这些结构使用常见的微加工技术的可能性。

英文摘要:

Laser-driven acceleration holds great promise for significantly improving accelerating gradient. However, scaling the conventional process of structure-based acceleration in vacuum down to optical wavelengths requires a substantially different kind of structure. We require an optical waveguide that (1) is constructed out of dielectric materials, (2) has transverse size on the order of a wavelength, and (3) supports a mode with speed-of-light phase velocity in vacuum. Photonic crystals--structures whose electromagnetic properties are spatially periodic--can meet these requirements. We discuss simulated photonic crystal accelerator structures and describe their properties. We begin with a class of two-dimensional structures which serves to illustrate the design considerations and trade-offs involved. We then present a three-dimensional structure, and describe its performance in terms of accelerating gradient and efficiency. We discuss particle beam dynamics in this structure, demonstrating a method for keeping a beam confined to the waveguide. We also discuss material and fabrication considerations. Since accelerating gradient is limited by optical damage to the structure, the damage threshold of the dielectric is a critical parameter. We experimentally measure the damage threshold of silicon for picosecond pulses in the infrared, and determine that our structure is capable of sustaining an accelerating gradient of 300 MV/m at 1550 nm. Finally, we discuss possibilities for manufacturing these structures using common microfabrication techniques.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

↑