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arXiv · 2605.02512

Direct Time-Domain Observation of l-Doubling via Centrifugal-Distortion Pre-compensation

Inbar Sternbach·Kfir Rutman Moshe·Amit Beer·Soumitra Hazra·Sharly Fleischer
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Abstract

We demonstrate direct time-domain observation of l-doubling contributions in molecular rotational dynamics using shaped femtosecond laser pulses. By imposing a tailored spectral phase on the excitation pulse, we pre-compensate centrifugal distortion, which otherwise leads to temporally broadened, multi-cycle revival structures that obscure fine rotational features. A cubic spectral phase [Phys. Rev. A 107, 053108 (2023)] compresses selected revivals into near single-cycle events, in agreement with an analytic expression derived from molecular rotational constants, enabling predictive pulse design beyond numerical optimization. The resulting distortion-free revivals reveal temporally separated l-doubling contributions that remain unresolved in conventional impulsive alignment experiments. The method proves robust against experimental imperfections, including spatial light modulator discretization. While selective control of individual l-doubling components becomes feasible, here we focus on their direct observation in the time domain.

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Inbar Sternbach, Kfir Rutman Moshe, Amit Beer, Soumitra Hazra, Sharly Fleischer. 2026-05-04. Direct Time-Domain Observation of l-Doubling via Centrifugal-Distortion Pre-compensation. https://arxiv.org/abs/2605.02512

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