Nanostructured plasmonic materials and methods of making and use thereof

A system comprising:

• a nanostructured plasmonic material comprising:
• a first nanostructured layer comprising a first layer of a first plasmonic material permeated by a first plurality of spaced-apart holes, wherein the first plurality of spaced apart holes comprise a first array defined by a first unit cell, the first unit cell having:
• a first principle axis and a second principle axis with a first included angle between the first principle axis and the second principle axis;
• wherein the first principle axis has a length that is the distance separating each hole in the first array from its neighboring hole (edge to edge) along the first principle axis;
• wherein the second principle axis has a length that is the distance separating each hole in the first array from its neighboring hole (edge to edge) along the second principle axis;
• and
• a second nanostructured layer comprising a second layer of a second plasmonic material permeated by a second plurality of spaced-apart holes, wherein the second plurality of spaced apart holes comprise a second array defined by a second unit cell, the second unit cell having:
• a first principle axis and a second principle axis with a second included angle between the first principle axis and the second principle axis;
• wherein the first principle axis has a length that is the distance separating each hole in the second array from its neighboring hole (edge to edge) along the first principle axis;
• wherein the second principle axis has a length that is the distance separating each hole in the second array from its neighboring hole (edge to edge) along the second principle axis;
• wherein the second nanostructured layer is located proximate the first nanostructured layer;
• and
• wherein the first principle axis of the first array is rotated at a rotation angle compared to the first principle axis of the second array;
• and
• a light source configured to illuminate the nanostructured plasmonic material with circularly polarized light.