Freiburg 2024 – scientific programme

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MO: Fachverband Molekülphysik

MO 7: Poster: Spectroscopy

MO 7.17: Poster

Tuesday, March 12, 2024, 17:00–19:00, Tent C

Cogwheel phase cycling in action-based two-dimensional spectroscopy — •Stefan Müller, Ajay Jayachandran, and Tobias Brixner — Institut für Physikalische und Theoretische Chemie, Universität Würzburg, Am Hubland, 97074 Würzburg

Coherent two-dimensional (2D) spectroscopies, which detect an action-based signal instead of a coherent signal, have become increasingly popular in recent years. These signals include photoions, internal or external photocurrents, and fluorescence. To extract the coherent information from the incoherent signal, a procedure such as phase cycling can be employed, which is usually carried out in a “nested” fashion, i.e., each pulse phase is incremented sequentially. Here we adapt a procedure from nuclear magnetic resonance spectroscopy, “cogwheel phase cycling,” in which all pulse phases are varied simultaneously in increments given by so-called winding numbers [1]. We show how to perform a numerical search for these winding numbers. Using a pulse-shaper-assisted setup for fluorescence-detected 2D spectroscopy, we demonstrate that fourth-order and higher-order signals can be acquired with fewer cogwheel phase-cycling steps compared to nested phase cycling while maintaining the same signal selectivity [2]. We predict considerable time savings for various pulse-shaper-based multidimensional spectroscopies.

[1] M. H. Levitt et al., J. Magn. Reson. 155, 300–306 (2002).

[2] A. Jayachandran et al., J. Phys. Chem. Lett. 13, 11710 (2022).

Keywords: 2D spectroscopy; phase cycling; fluorescence detection; pulse shaping