Widely tuneable coherent light source necessary for attosecond condensed matter experiments

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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.**