Picosecond pulse-shaping for strong three-dimensional field-free alignment of generic asymmetric-top molecules

Terry Mullins; Evangelos Thomas Karamatskos; Joss Wiese; Jolijn Onvlee; Arnaud Rouzée; Andrey Yachmenev; Sebastian Trippel; Jochen Küpper

arXiv · 2009.08157

Picosecond pulse-shaping for strong three-dimensional field-free alignment of generic asymmetric-top molecules

Terry Mullins·Evangelos Thomas Karamatskos·Joss Wiese·Jolijn Onvlee·Arnaud Rouzée·Andrey Yachmenev·Sebastian Trippel·Jochen Küpper

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Abstract

Fixing molecules in space is a crucial step for the imaging of molecular structure and dynamics. Here, we demonstrate three-dimensional (3D) field-free alignment of the prototypical asymmetric top molecule indole using elliptically polarized, shaped, off-resonant laser pulses. A truncated laser pulse is produced using a combination of extreme linear chirping and controlled phase and amplitude shaping using a spatial-light-modulator (SLM) based pulse shaper of a broadband laser pulse. The angular confinement is detected through velocity-map imaging of H$^+$ and C$^{2+}$ fragments resulting from strong-field ionization and Coulomb explosion of the aligned molecules by intense femtosecond laser pulses. The achieved three-dimensional alignment is characterized by comparing the result of ion-velocity-map measurements for different alignment directions and for different times during and after the alignment laser pulse to accurate computational results. The achieved strong three-dimensional field-free alignment of $\langle \cos^{2}δ\rangle=0.89$ demonstrates the feasibility of both, strong three-dimensional alignment of generic complex molecules and its quantitative characterization.

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Terry Mullins, Evangelos Thomas Karamatskos, Joss Wiese, Jolijn Onvlee, Arnaud Rouzée, Andrey Yachmenev, Sebastian Trippel, Jochen Küpper. 2022-02-22. Picosecond pulse-shaping for strong three-dimensional field-free alignment of generic asymmetric-top molecules. https://arxiv.org/abs/2009.08157

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