Terahertz Acousto-Optics: From Nano-to Picotechnology

提出的目标是探索一种基于超快声学的新方法，用于通过高强度应变脉冲控制凝聚态系统中的电子态。这些应变脉冲是光学产生的，可以很好地控制它们在皮秒(Ps)或亚ps范围内的持续时间以及导致皮秒(PM)晶格扭曲的幅度。该方案由两部分组成：第一部分是对嵌入在受限光子几何结构中的半导体量子结构中载流子的能级进行调制，从而对这些能级之间的自发或受激发射的能量和强度进行PS控制。最终可能会进入新的量子光学区域，在这种区域中，谐振器真空场比光学共振的拉比逆谱宽“抖动”得更快，甚至比光-物质相互作用强度给出的拉比逆频率还要快。第二部分将讨论探索性研究的其他广泛领域。例如：(1)应变脉冲可用于实现运行的量子结构以接近声音的速度移动，从而潜在地传输载流子；(2)电子能级的调制将被转移到其他材料类别，如强关联材料、超导体等，以改变其性质或诱导相变。(3)脉冲还可用于显微镜目的，通过该目的，内部结构可以非侵入性地以纳米分辨率成像。

The proposal objective is exploration of a novel methodology, based on ultrafast acoustics, for controlling the electronic states in condensed matter systems by high intensitye strain pulses. Generated optically, these strain pulses can be well controlled with respect to their duration in the picosecond (ps) or sub-ps range and their amplitude leading to picometer (pm) crystal lattice distortions. The proposal consists of two parts: In the first one the energy levels of carriers in semiconductor quantum structures embedded in confined photon geometries shall be modulated, leading to a ps-control of energy and intensity of the spontaneous or stimulated emission from optical transitions between these levels. Eventually new regimes of quantum optics may be entered, in which the resonator vacuum field is “shaken” faster than the Rabi inverse spectral width of the optical resonance, or even faster than the inverse Rabi frequency given by the strength of light-matter interaction. Other broad fields of exploratory research will be addressed in the second part. Examples are: (1) The strain pulses may be used to realize running quantum structures moving at a speed close to thatof of sound and thereby potentially transporting carriers; (2) The modulation of electron energy levels will be transferred to other material classes such as strongly correlated materials, superconductors etc. for modifying their properties or inducing phase transitions.(3) The pulses may be used also for microscopy purposes by which internal structures may be imaged with nanometer resolution non-invasively.