Light-matter interactions in aligned silver nanorod arrays

This study presents an experimental evaluation of the light-matter interactions in silver nanorod arrays of various lengths fabricated by electron-beam physical vapor deposition. The reflectance of nanorod arrays is found to decrease with increasing nanorod length, reaches to a minimum and then again increases with increasing length. Since nanorod arrays are subwavelength structures, the decrease in reflectance is primarily due to surface plasmon resonance. At the tip of the nanorods, the light excites the surface plasmons, which propagate along the conductor-dielectric interface. Hence, longer and consequently higher surface area nanorod arrays provide more dielectric-conductor interface for light to couple with the surface plasmons and more surface to scatter resulting in lower reflectance.