CAREER: Next Generation Photomixer-Based Terahertz Sources

目的：本CAREER项目旨在通过研究在电信波长泵浦的新一代等离子体分布锗光电混合器来解决现有光电混合器的输出功率限制。通过解决传统光电混合器热击穿的主要障碍，该技术有望提供比现有技术高几个数量级的太赫兹功率水平。知识优势：在这项研究计划中，PI将首次研究使用Ge作为解决光电混合器热击穿问题的有前途的候选材料。该项目还旨在研究分布式等离子体接触电极的使用，以进一步提高锗光电混合器的量子效率。等离子体电极有望显著提高泵浦耦合效率，同时实现光生成载流子的超高速收集。此外，分布式光电混合器结构减轻了与高强度光泵相关的非理想效应，如载流子筛选效应和过度加热。广泛影响：太赫兹源的前景应用是高性能太赫兹成像和光谱系统的发展。该职业计划的教育部分旨在将太赫兹技术新兴领域的教育与研究活动相结合。新的研究生课程将被开发，本科生将通过教学模块、暑期项目和高级设计项目接触到基本的太赫兹概念。在推广、K12活动、招募和保留妇女以及代表性不足的少数民族方面所做的努力将增加太赫兹工程师和科学家的供应，并进一步扩大该计划的影响。

Objective: This CAREER project aims to address the output power limitation of existing photomixers by investigating a new generation of plasmonic distributed Ge photomixers pumped at telecom wavelengths. By tackling the major obstacle of thermal breakdown of conventional photomixers, the proposed technology is expected to offer terahertz power levels that are orders of magnitude higher than is currently available from existing technologies.Intellectual Merits: In this research plan, the PI will investigate, for the first time, the use of Ge as a promising candidate to tackle the thermal breakdown problem of photomixers. The PI also aims to investigate the use of distributed plasmonic contact electrodes to further improve the quantum efficiency of Ge photomixers. Plasmonic electrodes are expected to significantly enhance the pump coupling efficiency, while enabling ultra-high-speed collection of photo-generated carriers. Moreover, distributed photomixer architectures mitigate the non-ideal effects associated with the high intensity optical pumps, such as the carrier screening effect and excessive heating.Broad Impacts: Promising application of the terahertz source is in development of high-performance terahertz imaging and spectrometry systems. The educational component of this CAREER program intends to integrate education with research activities in the emerging field of terahertz technology. New graduate courses will be developed and undergraduates will be exposed to basic terahertz concepts through teaching modules, summer programs and senior design projects. Efforts in outreach, K12 activities, recruitment and retention of women, and under-represented minorities, will increase the supply of terahertz engineers and scientists, and further broaden the influence of the program.