Dissipation-driven optomechanical control of diffraction grating through collective molecular interactions

Molecular cavity optomechanics (COM), with its strong optomechanical interaction and ultrasmall mode volumes, provides an effective framework for manipulating light at the nanoscale. Here, we propose a theoretical technique for generating a reconfigurable diffraction grating in a molecular COM system, where a standing-wave (SW) control field and a weak probe field manipulate a molecular layer placed inside an optical cavity. We first explore molecular optomechanically induced transparency (OMIT) in this system is achievable at exceptionally low cavity quality Q factor and is tunable via molecular ensemble density, even exhibiting negative absorption (gain). We exploit this tunability that allows for precise control over the diffraction pattern of the probe field, facilitating the generation of first-, second-, and even third-order diffraction grating through adjustments to the cavity Q factor, molecular ensemble density, and SW control beam power. Our findings thus demonstrate the potential of the molecular COM system for controlled nanophotonics, paving the way for a new class of configurable plasmonic grating and optical devices.