Fano Resonance and Slow-to-Fast Light Conversion in a Laguerre-Gaussian Rovibrational Cavity

The orbital angular momentum of optical fields, besides the amplitude, frequency, and phase, offers a new degree of freedom to manipulate the light-matter interactions. Here, Fano resonance and slow-to-fast light conversion in a Laguerre-Gaussian rovibrational cavity are investigated. The system consists of a Fabry–Pérot cavity with two spiral phase elements acting as the cavity mirrors, in which one of the spiral phase elements is fixed while the other can vibrate as well as rotate. Fano resonances are observed by adjusting the frequency detuning between the cavity and the driving fields. Double Fano resonances are observed for the Laguerre-Gaussian rovibrational cavity with different vibrational and rotational frequencies. Both the slow and fast light can be achieved with the same setup, which is controlled by the topological charge value and the frequency detuning between the probe and driving fields, thus providing a flexible and effective way to manipulate the slow-to-fast light conversion.