Widely tuneable coherent light source necessary for attosecond condensed matter experiments

阿秒科学（1 as = 10- 18 s），或阿秒科学，研究电子动力学。在气相中，原子或分子中的价电子运动是很好理解的。通过将这些测量技术-在阿秒时间尺度上启动和跟踪动力学-转移到凝聚态物质（CM），我们开辟了光-物质相互作用的一个大前沿，即量子和非线性光学，电光，CM物理和材料科学。此外，为attoscience创建的技术带来了前所未有的场灵敏度，不仅可用于下一代电子学，电气工程和光子学，还可用于分子检测，支架检测和生物传感。然而，要将attoscience技术从气相-其中吸收主要在真空紫外线中-转移到CM -其中吸收发生在可见光和短波长红外（SWIR）中-需要可广泛调谐的红外激光器。为了获得这些能量，高素质人员（HQP）将使用光学参量放大器（OPA）进行研究，以驱动实验。这项研究将在温莎大学的阿秒凝聚态实验（ACME）实验室进行。ACME HQP将利用CM中的阿秒技术来发现超快过程、控制工程材料中的电子运动并开发新的光子技术。OPA对于将这些技术转移到CM并进入光-物质相互作用的前沿领域至关重要。OPA有几个独特的属性。首先，它可以有效地将高强度的可见光超快激光脉冲转换为短波红外和中红外。其次，OPA的调谐将允许HQP研究从短波红外到中红外的辐射，跨越与安全和医疗应用相关的水和有机分子的光谱吸收带。此外，由OPA和能量调谐器产生的强场将在半导体材料的带隙附近获得不同的多光子效应。此外，阿秒分辨率需要对激光脉冲进行仔细的绝对相位控制，这在OPA中自然发生，但需要在激光器中使用繁琐的额外反馈电子器件。该OPA的应用将包括半导体中的高次谐波产生（HHG），以研究CM中的阿秒动力学，并创建一个有效的XUV光谱源。由于半导体中的HHG对外部场敏感，因此我们将使用对HHG信号的调制来在IR中暂时重建光学波形，测量水和生物相关吸收特征的振幅和相位。此外，对扰动场的灵敏度增加可以与其他已建立的技术相结合，例如原子力显微镜（AFM），用于纳米级的阿秒时间分辨率-这是两个不同研究领域的前所未有的组合。

Attosecond science (1 as = 10-18s), or attoscience, studies electron dynamics. In the gas phase, valence electron motion in an atom or molecule is well understood. By transferring these measurement techniques – initiating and following dynamics on an attosecond timescale – to condensed matter (CM), we open up a large frontier in light-matter interaction, namely quantum and nonlinear optics, electro-optics, CM physics, and materials science. Furthermore, the techniques created for attoscience have led to unprecedented field sensitivity that can be used not only for next-generation electronics, electrical engineering, and photonics, but also for molecular detection, standoff detection, and biosensing.***However, to transfer the techniques of attoscience from the gas phase – where absorption is mainly in the vacuum ultraviolet – to CM – where absorption occurs in the visible and short wavelength infrared (SWIR) – requires a widely tuneable infrared laser. To access these energies, highly qualified personnel (HQP) will perform research using an optical parametric amplifier (OPA) to drive the experiments. This research will be performed in the attosecond condensed matter experiments (ACME) laboratory at the University of Windsor. ACME HQP will leverage attosecond techniques in CM to discover ultrafast processes, control electronic motion in engineered material, and develop new photonics technologies. An OPA is essential to transfer these technologies to CM and access this frontier in light-matter interaction.***An OPA has several unique properties. First, it can efficiently convert high-intensity visible ultrafast laser pulses to the SWIR and mid-IR. Second, the tuneability of the OPA will allow for HQP to study radiation from SWIR to the mid-IR, spanning spectroscopic absorption bands of water and organic molecules that are relevant to security and medical applications. Furthermore, the strong fields generated by an OPA and energy tuneability will access different multiphoton effects near the bandgap of semiconductor materials. Additionally, attosecond resolution requires careful absolute phase control of the laser pulse, which naturally occurs in an OPA but requires cumbersome additional feedback electronics in a laser.***The applications of this OPA will include high harmonic generation (HHG) in semiconductors to study attosecond dynamics in CM and to create an efficient XUV source for spectroscopy. Because HHG in semiconductors is sensitive to external fields, we will use modulations to the HHG signal to temporally reconstruct optical waveforms in the IR, measuring the amplitude and phase of water and biologically relevant absorption signatures. Moreover, the increased sensitivity to perturbing fields can be leveraged with other established techniques such as atomic force microscopy (AFM) for attosecond time resolution at the nanoscale – an unprecedented combination of two disparate areas of research.**