Nonlinear Near Millimeter Wave Properties of Semiconducting Heterostructures

康奈尔大学建造了一台光泵浦的近毫米波高强度激光器，用于测量太赫兹频段二维电子气结构的非线性极化率。围绕这台仪器，提出了一个产学研合作计划，对IBM提供的高迁移率二维EG样品的远红外非线性特性进行了测量。一个目标是通过将高强度共振辐射调谐到自然量子跃迁频率来驱动集体2-DEG电子模式远离平衡。由于目前对2-DEG系统的非线性高频特性的研究还很少，因此提出了一些不同的实验。这些措施包括在高达11特斯拉的磁场中对子带状态和回旋共振模式进行饱和测量，识别共振和非共振热电子效应，观察倍频周期，以及预计将在2-DEG表层发生并以高强度出现在样品中的新型二次谐波产生。还建议继续研究半导体中缺陷处的持久红外烧孔现象，以探索铝-镓-砷化合物中DX中心和硅中双空位的动态。

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.