Cavity-Free Mode Control of Superfluorescence from Thermal Gas
Phys. Rev. Lett. 136, 233603 – Published 11 June, 2026
DOI: https://doi.org/10.1103/cbxq-8n45
Abstract
Transverse-mode control of light has traditionally relied on optical cavities, whereas recent cavity-free approaches based on periodically arranged cold atoms that exploit collective radiation have attracted increasing attention. Here, we demonstrate a new cavity-free method applicable to thermal gases. Using crossed femtosecond laser pulses, we excite rubidium atoms and observe superfluorescence (SF) emitted during an ultrafast relaxation process. We demonstrate successful control of the transverse modes of SF when the interference fringes formed by the crossed beams are resonant with half the SF wavelength. This ultrafast, cavity-free approach provides a versatile playground for studying interactions between quantum many-body systems and well-defined electromagnetic fields in free space.
