Reflective plasmonic color filters based on lithographically patterned silver nanorod arrays.

We demonstrate reflection-mode plasmonic color filters based on lithographically patterned silver nanorods with ultrasmall inter-rod gaps. Fine and effective tuning of the plasmon resonance is shown by varying array periodicities. We determine the dependence of reflected intensity on diameter/periodicity ratio and then develop reflective plasmonic color filters using dense nanorod arrays. Experimental results agree well with theoretical calculations. Our approach is potentially useful for plasmon-assisted sensing, imaging and displays.