Nano-gap grating devices with enhanced optical properties and methods of fabrication

Abstract

A method of producing a grating structure comprises the steps of forming a stamp from flexible plastic material, the stamp including a negative of a periodic grating pattern on a first surface; forming an ink by applying a polymer film to the stamp, the ink including a first surface and an opposing second surface, wherein the first surface of the ink contacts the first surface of the stamp such that the ink retains a positive of the periodic grating pattern; placing the ink and the stamp on a substrate such that the second surface of the ink contacts an upper surface of the substrate; and removing the stamp from the ink by applying a tensional force to one edge of the stamp.

Having thus described various embodiments of the invention, what is claimed as new and desired to be protected by Letters Patent includes the following: 
     
         1 . A grating structure comprising:
 a base layer positioned on the substrate, the base layer including
 a first surface with a plurality of grating elements positioned adjacent one another, each grating element including a longitudinal tip, a longitudinal plateau, and a longitudinal nanogap, and 
   a contiguous first functional layer conformally covering the base layer producing an enhanced fluorescence of a sample,   wherein the first functional layer includes a plurality of nanospurs forming a plurality of peaks abutting one another along the length of the longitudinal tip producing additional localized electromagnetic field enhancement.   
     
     
         2 . The grating structure of  claim 1 , wherein the longitudinal nanogap has a width ranging from approximately 10 nm to approximately 30 nm and the longitudinal tip has a width ranging from approximately 10 nm to approximately 30 nm. 
     
     
         3 . The grating structure of  claim 1 , wherein the first functional layer is metallic, and wherein the first functional layer is approximately 100 nm thick. 
     
     
         4 . The grating structure of  claim 1 , wherein the first functional layer is made of silver. 
     
     
         5 . The grating structure of  claim 1 , wherein the first functional layer is made of a dielectric, and wherein the first functional layer is between approximately 100 nm and approximately 200 nm thick. 
     
     
         6 . The grating structure of  claim 1 , wherein the first functional layer is made of titanium dioxide.