Terahertz Electro-Optics and Intersubband Micro-Plasmonics in Semiconductor Quantum Well Devices

*非技术摘要*本研究计划探索半导体器件(在加州大学圣巴巴拉分校设计和制造)在0.1至10 THz电磁频谱的“太赫兹(THz)间隙”中的响应。1太赫兹的频率相当于每秒1万亿(1012)个周期，比手机广播的频率快1000倍，比绿光的频率低500倍。将探索一种新型的太赫兹辐射探测器，可能用于安全、医学和非破坏性材料测试等应用。这个探测器的核心是一层薄薄的电子“气体”。电子将被强迫垂直于这一层，以寻找同时存在两种稳定的工作状态(“光学双稳”，潜在地用作太赫兹激活的开关)、自发振荡(潜在的太赫兹源)和由周期驱动引起的“混沌”电流(在量子力学系统中通常不能观察到混沌)。强太赫兹辐射还将用于增强半导体光学设备的功能，例如用于通过光纤电缆传输信息的光学调制器。本科生、研究生和博士后研究人员将接受广泛的实验培训。与PI一起，他们将为当地的K-12学校带来新的外展材料。*技术摘要*本研究项目探索加州大学圣巴巴拉分校设计和制造的半导体量子器件对0.1至10太赫兹频谱区域的电磁场的响应。一种新型的天线耦合太赫兹辐射探测器，基于半导体量子阱中的子带间跃迁，将被用作研究一系列非线性量子现象的平台，这些现象预计在二维电子气被强迫垂直于其所在平面时发生。理论上的非线性是由强的电子-电子相互作用引起的。强太赫兹辐射也将被用来寻找对量子井近红外传输的修改。预测包括在强太赫兹驱动下任意微弱的近红外光束的交叉调制。本科生、研究生和博士后研究人员将接受广泛的实验培训。他们和PI还将为当地的K-12学校带来新的外展材料。

*****NON-TECHNICAL ABSTRACT**** This research program explores the response of semiconductor devices (designed and fabricated at UC Santa Barbara) in the "terahertz (THz) gap" of the electromagnetic spectrum between 0.1 and 10 THz. A frequency of 1 THz corresponds to 1 trillion (1012) cycles per second, 1000 times faster than the frequency at which cell phones broadcast, and 500 times lower than the frequency of green light. A new kind of detector for terahertz radiation will be explored, potentially useful for applications including security, medicine, and non-destructive materials testing. At the heart of this detector is a "gas" of electrons confined in a thin layer. The electrons will be forced perpendicular to the layer to search for the simultaneous existence of two stable operating states ("optical bistability," potentially useful as a terahertz-activated switch), spontaneous oscillation (a potential terahertz source) and a "chaotic" current induced by periodic driving (chaos is not normally observed in quantum mechanical systems). Strong terahertz radiation will also be used to enhance the functionalities of semiconductor optical devices, such as optical modulators used to transmit information over fiber-optic cables. Undergraduates, graduate students and post-doctoral researchers will receive broad experimental training. Along with the PI, they will bring novel outreach materials to local K-12 schools. *****TECHNICAL ABSTRACT**** This research program explores the response of semiconductor quantum devices, designed and fabricated at UC Santa Barbara, to electromagnetic fields in the region of the spectrum between 0.1 and 10 THz. A new kind of antenna-coupled detector for terahertz radiation, based on intersubband transitions in semiconductor quantum wells, will be used as a platform for investigating a wide range of nonlinear quantum phenomena which are predicted to occur when a 2-D electron gas is forced perpendicular to the plane in which it is confined. The nonlinearity arises in theories from the strong electron-electron interaction. Strong THz radiation will also be used to search for modifications of the near-IR transmission of quantum wells. Predictions include cross-modulation of arbitrarily weak NIR beams in the presence of strong THz driving. Undergraduates, graduate students and post-doctoral researchers will receive broad experimental training. They and the PI will also bring novel outreach materials to local K-12 schools.