Intense few-cycle mid-infrared laser source

固体中强场现象的研究可以极大地受益于在光谱的中红外部分中使用强的、周期数少的激光源。中红外激光器更适合在低带隙材料中使用强场，例如半导体，捕光钙钛矿，2-D材料以及生物材料。在平均带隙能量为1-2 eV的情况下，暴露于光场（1 eV-2 eV）的半导体在可以有效地触发极端非线性响应之前遭受光学损伤。中红外脉冲可以克服这一障碍。 中红外场和光场将允许激发和探测更多自由度，而不是电子响应，如声子。中红外脉冲和光学阿秒脉冲的结合可以使动力学微微观的发展成为可能，即在空间和时间上探索物质中电子动力学的能力。从纳米结构材料中驱动强场发射的可能性-我们小组中一条新的和非常有前途的研究路线，可以再次受益于超短光脉冲的持续时间，但它们的能量非常接近固体的典型功函数（< 5 eV），这再次对可以施加的最大电场施加了强大的限制。我们将在下文中看到，如果驱动场的载流子能量向光谱的中红外部分移动，那么提供产生和控制电子脉冲潜力的光发射实验可以显着改善。我们建议采购一个中红外（2微米），相位稳定，几个周期的激光系统的能量范围为~250微焦耳。该系统将在固体强场现象的一系列研究中发挥重要作用。

The study of strong field phenomena in solids can tremendously benefit from the use of intense, few-cycle laser sources in the mid-infrared part of the spectrum. Lasers at the mid-infrared are more appropriate for exercising strong fields in low band gap materials such as semiconductors, light-harvesting perovskites, 2-D materials, as well as materials of biological interest. With an average bandgap energy of the order of 1-2 eV, semiconductors exposed to optical fields (1 eV -2 eV) suffer optical damage before an extreme nonlinear response can be efficiently triggered. Mid-infrared pulses can allow overcoming this barrier. Mid-infrared field and optical fields will allow excitation and probing of more degrees of freedom other than electronic response such as phonons. The combination of mid-infrared pulses and optical attosecond pulses could allow the development of dynamics picoscopy, that is the capability to explore electron dynamics in matter both in space and time. The possibility to drive strong-field emission from nanostructured materials—a new and highly promising research route in our group, can once again benefit from the duration of ultrashort optical pulses but their energy is very close to the typical work function of solids (< 5 eV) imposing once again a formidable limit as to the maximum electric field that can be exercised. We will see bellow that photoemission experiments offering the potential for generating and controlling electron pulses can be dramatically improved if the carrier energy of the driving field shift towards the mid-infrared part of the spectrum. We propose the procurement of a mid-infrared (2 microns), phase-stabilized, few-cycle laser system with energy in the range of ~250 microjoule. This system will play an essential role for a range of studies of strong field phenomena in solids.