Duty cycle dependency of the optical transmission spectrum in an ultrathin nanostructured Ag film

Plasmonic color filters with a single periodically patterned metal film structure deposited on a glass substrate have been an attractive research hotspot due to its ease of fabrication, durability and flexible color tunability. Previous researches mostly focused on the periodicity, shape, thickness dependency of the transmission spectrum. Here, we both theoretically and experimentally studied the influence of duty cycle to the transmission spectrum of ultrathin Ag film patterned with one dimensional grating. It is found that the transmission minimum could be largely tuned by varying the duty cycle. The physical mechanism for the degradation of the transmission spectrum when increasing duty cycle and period of Ag grating has been discussed.