Unveiling the Loss\nMode Enabled Tunable Plasmonic\nChirality at Flat Metal Surface

Plasmonic chirality has garnered significant interest\nin the past\ndecade due to its enhanced chiral light–matter interactions.\nCurrent methods for achieving plasmonic chirality often rely on complex\nnanostructures or metamaterials, which are hampered by intricate fabrication\nprocesses. In this work, we present an approach to generate plasmonic\nchiral structured surface plasmon polariton (s-SPP) fields on a single,\nflat metal surface, bypassing elaborate fabrication techniques. The\nplasmonic chiral s-SPP fields are excited by the superposition of\nmultiple differently oriented transverse magnetic polarized plane\nwaves. We demonstrate, both theoretically and experimentally, the\nflexible tuning of chiral plasmonic patterns by adjusting the symmetry\nand phase differences of the incident waves. This method provides\na facile mean to optically tailor plasmonic chiral properties on a\nsubwavelength scale, offering potential applications in sensing, enantioselective\nreactions, imaging, and reconfigurable chiral switches.