Geometrical control of spatio-temporal coherence in femtosecond rotational coherent Raman scattering

We present a theoretical framework for spatial phase coherence in femtosecond rotational coherent Raman scattering (fs-RCRS), demonstrating how phase-matching geometry couples temporal dynamics to the transverse structure of the detected signal. On this basis, we identify two configurations with significant practical implications. In one case, the geometry allows single-shot measurements of collisional dephasing and rotational energy transfer, as well as multi-species detection. In the other, the geometry provides a straightforward scheme for one-dimensional thermometry. Together, these results establish geometry-driven space-time coherence as a versatile tool for femtosecond rotational spectroscopy and diagnostics.