Lattice Resonances in Periodic Arrays of Time‐Modulated Scatterers

ABSTRACT Lattice resonances are collective modes in periodic arrays of scatterers, arising from coherent interactions that yield stronger and spectrally narrower responses than those of the individual constituents. While extensively explored in time‐invariant systems, recent advances in time‐varying photonics offer new opportunities to exploit these modes. Here, we investigate lattice resonances in arrays of time‐modulated scatterers using a dipolar approximation combined with time‐Floquet theory, modeling each scatterer as a harmonic oscillator with periodically varying optical properties. Starting from the dynamics of a single scatterer, we identify the complex eigenfrequencies governing its response and show that, under suitable modulation amplitude and frequency, the imaginary part of one of them vanishes, leading to an amplification singularity. Extending this analysis to periodic arrays reveals a complex interplay between temporal modulation and lattice resonances that introduces a richer spectral amplification behavior than in isolated scatterers. Importantly, amplification occurs at significantly lower modulation strengths, facilitated by the enhanced light‐matter interaction and increased lifetime of these collective modes. Our work establishes a simple framework for understanding lattice resonances in time‐modulated arrays, enabling dynamic control and amplification of these modes. These findings open pathways toward the next generation of light sources and nonreciprocal photonic devices.