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| Title | Time-resolved nonlinear microspectroscopy with Gaussian beams: Photon echo and spatially encoded coherence | ||||
| Date | 2026-04-13 | Attachment | , , , , , , , , | ||
Time-resolved nonlinear microspectroscopy with Gaussian beams: Photon echo and spatially encoded coherenceCho, MH (Cho, Minhaeng) Journal of Chemical Physics, 2025, Volume 162, 214204. We extend our theoretical framework for time-resolved nonlinear microspectroscopy [M. Cho, J. Chem. Phys. 162, 124201 (2025)] to coherent four-wave-mixing spectroscopy using paraxial Laguerre-Gaussian (LG) beams. Unlike pump-probe or transient absorption techniques, photon echo is highly sensitive to the spatial phase structure of LG beams. This sensitivity arises because coherence evolution in inhomogeneously broadened absorbers depends on the radial and azimuthal indices of the LG modes used in the write-and-read processes within the photon echo configuration. Recent advances in spatial light modulators, metasurfaces, and ultrafast laser techniques have significantly improved spatial and temporal control over quantum materials. These innovations enable new approaches to studying heterogeneous systems, developing multidimensional microspectroscopy, and exploring alternative quantum information storage methods. In this work, we investigate photon echo signals generated by LG beams and derive analytical expressions for rephasing and non-rephasing photon echoes. Our results reveal how beam parameters influence nonlinear spatiotemporal responses, capturing spatial variations in pulse amplitudes, phases, and inhomogeneity-induced dephasing and rephasing. We show that customized ultrafast pulses and structured spatial light fields can enhance the spatial separation of photon echo signals and increase the density of stored quantum information. This work advances nonlinear molecular spectroscopy and quantum information science by leveraging structured light fields and ultrafast optics. |
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