CAREER: Time-Resolved Nonlinear Terahertz Spectroscopy

该研究项目提出了一种用于时间分辨太赫兹（Thz）光谱的新型超强、超短脉冲电磁辐射源的开发。这个桌面辐射源将发射亚皮秒的电磁脉冲，具有太赫兹波段和千兆瓦（GW）的峰值功率。该技术是利用放大飞秒激光束照射大孔径半导体发射体，在半导体表面和界面的静电场中注入自由载流子，产生快速瞬变电流产生电磁辐射。由于亚毫米波脉冲所携带的能量主要来源于存储在表面的静电能量，而不是来自入射的激光能量，因此辐射的总能量可以很好地超过激光束的入射能量。该学术提案的结果是需要为伦斯勒大学的光学物理项目开发一个新的课程。一项试点计划正在开发，以提高学生的学习和动机，通过计算机为基础的互动教学，使用图形，多媒体，数值模拟和动手实验。为本科生准备的先进光电实验室将配备最先进的设备和仪器。计算机辅助现代光学教室正在建设中。本科生的研究参与被强烈强调，以紧密结合实验和课堂工作活动。

This research project proposes the development of a novel source of ultra-intense, ultrashort pulsed electromagnetic radiation for time-resolved terahertz (Thz) spectroscopy. This table-top radiation source will emit subpicosecond electromagnetic pulses with Thz bandwith and gigawatt (GW) peak power. The technique consists of using an amplified femtosecond laser beam to illuminate a large-aperture semiconducting emitters, and to generate electromagnetic radiation produced by the rapid current transients due to optical injection of free carriers into the static electric fields associated with the semiconductor surfaces and interfaces. Since the energy carried by submillimeter-wave pulses is derived mainly from the electrostatic energy capacitively stored at the surface rather than from the incident laser energy, the total energy of the radiation can well exceed the incident of the laser beam. The academic proposal results from a need to develop a new curriculum for the Optical Physics Program at Rensselear. A pilot program is being developed to improve student learning and motivati on through computer-based interactive teaching using graphics, multi-media, numerical simulations, and hands-on experiments. The proposed Advanced Optoelectronic Laboratory for undergraduates will be furnished with state-of-the-art equipment and instrumentation. A computer-assisted Modern Optics Teaching Room is under construction. Undergraduate student research participation is strongly emphasized to tightly couple experimental and class work activities.