Closed loop coherent control of electronic transitions in gallium arsenide.
Closed loop coherent control of electronic transitions in gallium arsenide.
复制标题
DOI：
10.1021/jp110869f
复制
发表时间：
2011-02
期刊：
影响因子：
--
通讯作者：
S. Singha;Zhan Hu;R. Gordon
中科院分区：
文献类型：
--
作者：
S. Singha;Zhan Hu;R. Gordon
采用遗传算法控制GaAs（100）的光致发光（PL）。空间光调制器利用发射反馈来优化超短激光脉冲的光谱相位分布。大多数实验使用正弦相位函数来优化特定波长范围内的集成PL光谱，相位函数的振幅和周期被视为遗传参数。仅在一代后，信号就增加了一个数量级，并且在15代后获得了由三个间隔约0.8 ps的等间隔脉冲组成的优化波形。考察了通量、极化、子脉冲的相对相位和优化后的光谱线的光谱范围对光谱线的影响。此外，还利用SLM各像元的相位作为遗传变量进行了初步实验。用布里渊区l -谷中的电子-空穴对复合来识别PL谱。控制是通过等离子体电子的相干操纵来实现的。提出了热电子激发晶格声子，进而将载流子散射到l -谷。
A genetic algorithm was used to control the photoluminesce-nce (PL) from GaAs(100). A spatial light modulator (SLM) used feedback from the emission to optimize the spectral phase profile of an ultrashort laser pulse. Most of the experiments were performed using a sine phase function to optimize the integrated PL spectrum over a specified wavelength range, with the amplitude and period of the phase function treated as genetic parameters. An order of magnitude increase in signal was achieved after only one generation, and an optimized waveform, consisting of three equally spaced pulses approximately 0.8 ps apart, was obtained after 15 generations. The effects of fluence, polarization, relative phase of the subpulses, and spectral range of the optimized PL were investigated. In addition, preliminary experiments were performed using the phases of individual pixels of the SLM as genetic variables. The PL spectrum is identified with recombination of electron-hole pairs in the L-valley of the Brillouin zone. Control is achieved by coherent manipulation of plasma electrons. It is proposed that hot electrons excite lattice phonons, which in turn scatter carriers into the L-valley.