Experimental and Theoretical Investigation of Ultrafast Coherent Phenomena in Semiconductors

在这个项目中，我们将研究 半导体非平衡态 理论中的多体效应 实验合作的努力。 我们将试图证明 拉比的第一次观察 振荡（RO）和共振 强飞秒传输 半导体中的脉冲 Rabi 振荡和共振脉冲 传播，甚至自诱导 透明度（SIT），已经被发现 在原子系统中，但还没有 在半导体中观察到。 我们的多体计算 预测RO可能会出现在 半导体当飞秒 激光脉冲短于 采用移相T2时间。 同时，这些计算预测 强大的修改 脉冲传播和自感 半导体的透明度，如 与原子系统相比。 之一 我们的目标是执行交叉- 脉冲相关实验 调谐到激发共振， GaAs-AlGaAs多量子阱 样本来验证这些预测 并展示了 半导体中的SIT 相对于原子系统。 我们计划从数量上 研究载流子弛豫， 量子威尔斯中的退相 如在井下的散装材料中， 定义条件。 从理论上讲， 我们最近发现了一种新的 体声波等离子体激元模 半导体适用于 非平衡载流子 分布。根据我们 计算，相关的超快 载流子-载流子散射， 失相应该是显著的 不同的内在，n-和p- 掺杂材料，因为 低动量态电子 主要负责 声等离子体激元阻尼。 光谱 增益区的烧孔 半导体将被执行， 和偏振退相时间 将使用以下宽度进行测量： 烧过的洞 这些 测量，这将是 与我们的计算相比， 应该能提供重要信息 关于载流子弛豫和失相 rates.

In this project we will investigate the semiconductor nonequilibrium many-body effects in a theory- experiment collaborative effort. We will attempt to demonstrate the first observation of Rabi oscillations (RO) and resonant propagation of strong femtosecond pulses in a semiconductor. Rabi oscillations and resonant pulse propagation, even self-induced transparency (SIT), have been seen in atomic systems, but have not yet been observed in semiconductors. Our many-body calculations have predicted that RO may be seen in semiconductors when femetosecond laser pulses shorter than the dephasing T2 times are employed. Also, these calculations predict significant modifications of strong pulse propagation and self-induced transparency in semiconductors, as compared to atomic systems. One of our goals is to perform cross- correlation experiments for pulses tuned to the excition resonance in a GaAs-AlGaAs multiple quantum well sample to verify these predictions and demonstrate the differences between SIT in semiconductors versus atomic systems. We plan to quantitatively investigate carrier relaxation and dephasing in quantum wells as well as in bulk materials under well- defined conditions. Theoretically, we recently found a new undamped acoustic plasmon mode in bulk semiconductors for suitable nonequilibrium carrier distributions. According to our calculations, the related ultrafast carrier-carrier scattering and dephasing should be significantly different for intrinsic, n- and p- doped materials, since the electrons in low momentum states are primarily responsible for the acoustic plasmon damping. Spectral hole burning in the gain region of semiconductors will be performed, and polarization dephasing times will be measured using the width of the burned holes. These measurements, which will be compared with our calculations, should yield important information on carrier relaxation and dephasing rates.