Nonlinear Near Millimeter Wave Properties of Semiconducting Heterostructures

美国康奈尔大学（Cornell University）研制了一种光抽运的近毫米波高强度激光器，用于测量二维电子气体（2- DEG）结构在太赫兹频率区域的非线性磁化率。提出了一项产学研合作研究计划，围绕该仪器，对IBM提供的高迁移率2- DEG样品的远红外非线性特性进行了测量。一个目标是用调谐到自然量子跃迁频率的高强度共振辐射驱动集体2-DEG电子模式远离平衡态。由于对2-DEG系统的非线性高频特性的研究很少，因此提出了许多不同的实验。其中包括在高达11特斯拉的磁场中对子带状态和回旋共振模式的饱和测量，共振和非共振热电子效应的识别，周期加倍的观察以及预测在2-DEG表层发生的新型二次谐波产生，并在高强度下出现在样品中。对半导体缺陷处持续红外孔燃烧的研究也被提出，并将努力用于探测砷化铝镓中DX中心的动态和硅中的距离。

An optically-pumped, near-mm-wave, high-intensity laser has been constructed at Cornell University for the purpose of measuring the nonlinear susceptibility of two dimensional electron gas (2- DEG) structures in the Terahertz frequency region. A collaborative Industry/University research program is proposed, entered around this instrumentation, in which measurements are made on the far infrared nonlinear properties of high mobility 2- DEG samples provided by IBM. One goal is to drive the collective 2-DEG electronic modes far from equilibrium with high intensity resonant radiation tuned to the natural quantum transition frequencies. Since very little research has been carried out as yet on the nonlinear high frequency properties of 2-DEG systems a number of different experiments are proposed. These include saturation measurements on the sub-band states and on the cyclotron resonance mode in magnetic fields up to 11 Tesla, identification of resonant and nonresonant hot electron effects, observation of period doubling and a new type of second harmonic generation predicted to occur for the 2-DEG surface layer and appears in the sample at high intensities. A continuation of the investigation of persistent IR hole burning at defects in semiconductors is also proposed with effort directed toward probing the dynamic of the DX center in aluminum-gallium-arsenide and the divacancy in silicon.