A photonic cavity, also known as an optical cavity, is a structure that confines electromagnetic radiation within a certain region or volume. It is typically composed of materials with different refractive indices, allowing light to be reflected and trapped within the cavity. Photonic cavities are widely used in various applications, including lasers, optical filters, sensors, and photonic integrated circuits.
The confinement of light within a photonic cavity leads to the formation of standing wave patterns, which depend on the geometry and optical properties of the cavity. These standing waves result in resonant modes with specific frequencies, which are determined by the cavity dimensions and the refractive indices of the materials involved. The resonant modes of a photonic cavity can enhance certain optical processes, such as absorption, emission, and light-matter interactions, making them crucial components in many optical devices and systems.