Photonic crystal sensors exploit deliberately engineered periodic dielectric structures to control the propagation, confinement, and spectral response of light. Their sensing capability arises from the strong dependence of photonic modes on changes in refractive index, absorption, geometry, surface loading, temperature, strain, or other environmental variables. By concentrating electromagnetic energy within carefully selected regions, photonic crystal […]
Introduction The optical spectrum of a photonic device is the measurable consequence of a complex interaction among geometry, material dispersion, electromagnetic boundary conditions, excitation state, fabrication variability, and environmental conditions. Whether the device is a wavelength-selective filter, metasurface, photonic crystal cavity, grating coupler, resonator, optical sensor, or nonlinear waveguide, its functional behavior is often summarized […]
