2020/01/25 by Ashley P. Fidler, Erika R. Warrick, Fidler, Ashley P. +9 · 1 citation
Chemistry · Physics and Astronomy · #Atomic Physics (physics.atom-ph) #FOS: Physical sciences #Laser-Matter Interactions and Applications #Optics (physics.optics) #Spectroscopy and Laser Applications #Spectroscopy and Quantum Chemical Studies
paper · pdf · doi:10.48550/arxiv.2001.09393
openalex publication_date 2020/01/25 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
Noncollinear wave-mixing spectroscopies with attosecond extreme ultraviolet\n(XUV) pulses provide unprecedented insight into electronic dynamics. In\ninfrared and visible regimes, heterodyne detection techniques utilize a\nreference field to amplify wave-mixing signals while simultaneously allowing\nfor phase-sensitive measurements. Here, we implement a self-heterodyned\ndetection scheme in noncollinear wave-mixing measurements with a short\nattosecond XUV pulse train and two few-cycle near infrared (NIR) pulses. The\ninitial spatiotemporally overlapped XUV and NIR pulses generate a coherence of\nboth odd (1snp) and even (1sns and 1snd) parity states within gaseous helium. A\nvariably delayed noncollinear NIR pulse generates angularly-dependent four-wave\nmixing signals that report on the evolution of this coherence. The diffuse\nangular structure of the XUV harmonics underlying these emission signals is\nused as a reference field for heterodyne detection, leading to cycle\noscillations in the transient wave-mixing spectra. With this detection scheme,\nwave-mixing signals emitting from at least eight distinct light-induced, or\ndressed, states can be observed, in contrast to only one light induced state\nidentified in a similar homodyne wave-mixing measurement. In conjunction with\nthe self-heterodyned detection scheme, the noncollinear geometry permits the\nconclusive identification and angular separation of distinct wave-mixing\npathways, reducing the complexity of transient spectra. These results\ndemonstrate that the application of heterodyne detection schemes can provide\nsignal amplification and phase-sensitivity, while maintaining the versatility\nand selectivity of noncollinear attosecond XUV wave-mixing spectroscopies.\nThese techniques will be important tools in the study of ultrafast dynamics\nwithin complex chemical systems in the XUV regime.\n