Methods of fabricating infrared bandpass filters and infrared bandpass filters fabricated thereby

1 . A method of fabricating an infrared (IR) bandpass filter, the method comprising:

forming metallic and dielectric spacer layers on a mold, the metallic and dielectric spacer layers comprising nanoscale-sized recesses or protuberances defined by the mold;

depositing a stress-absorbing layer on the dielectric spacer layer opposite the mold;

attaching a tape to a surface of the stress-absorbing layer opposite the dielectric spacer layer;

peeling the tape away from the mold to peel and delaminate from the mold a first intermediate structure comprising the metallic layer, the dielectric spacer layer, and the stress-absorbing layer that is attached to the tape;

removing the tape from the surface of the stress-absorbing layer of the first intermediate structure to form a second intermediate structure;

selectively removing the stress-absorbing layer from the second intermediate structure with a first solvent configured to dissolve the stress-absorbing layer to define a third intermediate structure comprising the metallic layer and the dielectric spacer layer; and

transferring the third intermediate structure to a receiver substrate to define the infrared (IR) bandpass filter, wherein the recesses or protuberances of the metallic and dielectric spacer layers are configured to function as quasi three dimensional (quasi 3D) plasmonic metal dielectric hybrid nanostructures.

2 . The method of claim 1 , wherein forming the metallic and dielectric spacer layers on the mold comprises:

providing the mold comprising an array of nanoscale-sized recesses or protuberances;

depositing a metallic material on the mold such that the metallic material is received within the recesses or between the protuberances of the mold to form the metallic layer thereon; and

depositing a dielectric material on the metallic layer that is received within the recesses or between the protuberances of the mold to form the dielectric spacer layer;

wherein the nanoscale-sized recesses or protuberances of the metallic and dielectric spacer layers are defined by the array of nanoscale-sized recesses or protuberances of the mold.

3 . The method of claim 2 , further comprising:

depositing a sacrificial material on the array of nanoscale-sized recesses or protuberances of the mold to form a sacrificial layer thereon prior to forming the metallic and dielectric spacer layers;

forming the metallic and dielectric spacer layers such that the sacrificial layer is between the mold and the metallic layer; and

performing an etching process to selectively remove the sacrificial layer prior to applying the force to the stress-absorbing layer to peel the first intermediate structure from the mold.

4 . The method of claim 3 , wherein the sacrificial material is a ductile metal.

5 . The method of claim 3 , wherein the metallic layer is a ductile metal.

6 . The method of claim 1 ,

wherein the tape comprises an adhesive, liquid-soluble film, and wherein the step of attaching the tape comprises applying the adhesive, liquid-soluble film to the stress-absorbing layer prior to applying the force to the stress-absorbing layer to peel the first intermediate structure from the mold;

wherein the step of peeling the tape away comprises applying the force to the stress-absorbing layer by pulling on the liquid-soluble film to peel the first intermediate structure from the mold, wherein the first intermediate structure comprises the liquid-soluble film, the metallic layer, the dielectric spacer layer, and the stress-absorbing layer; and

selectively removing the liquid-soluble film from the first intermediate structure with a second solvent configured to dissolve the liquid-soluble film prior to removing the stress-absorbing layer.

7 . The method of claim 2 , further comprising forming the array of nanoscale-sized recesses or protuberances of the mold by nanolithography.

8 . The method of claim 7 , wherein forming the nanolithography comprises electron beam (e beam) lithography.

9 . The method of claim 1 , wherein the metallic and dielectric spacer layers include the nanoscale-sized recesses defined by protuberances in the mold, each of the recesses representing a nanohole.

10 . The method of claim 1 , wherein the metallic and dielectric spacer layers include the nanoscale-sized protuberances defined by recesses in the mold, each of the protuberances representing a nanopost.

11 . The method of claim 1 , wherein the metallic layer comprises gold (Au).

12 . The method of claim 1 , wherein the dielectric spacer layer comprises an epoxy-based composition having a fracture strain of about 2% to about 3%.

13 . The method of claim 1 , wherein the stress-absorbing layer comprises an acrylic.

14 . The method of claim 1 , wherein the stress-absorbing layer is about 0.001 to 2 μm thick.

15 . The method of claim 1 , further comprising fabricating an additional infrared (IR) bandpass filter with the mold.

16 . A method for fabrication of an infrared (IR) bandpass filter, the method comprising:

providing a mold comprising an array of nanoscale-sized recesses or protuberances;

depositing a sacrificial material on the array of nanoscale-sized recesses or protuberances of the mold to form a sacrificial layer thereon;

depositing a metallic material comprising gold (Au) on the sacrificial layer such that the metallic material is received within the recesses or between the protuberances of the mold to form a metallic layer thereon;

depositing a dielectric material on the metallic layer that is received within the recesses or between the protuberances of the mold to form a dielectric spacer layer thereon;

depositing a stress-absorbing material on the dielectric spacer layer to form a stress-absorbing layer thereon;

performing an etching process to selectively remove the sacrificial layer;

applying an adhesive, water-soluble film to the stress-absorbing layer;

applying a force to the stress-absorbing layer by pulling on the water-soluble film to peel a first intermediate structure from the mold, wherein the first intermediate structure comprises the water-soluble film, the metallic layer, the dielectric spacer layer, and the stress-absorbing layer;

selectively removing the water-soluble film from the first intermediate structure by dissolving the water-soluble film with water to define a second intermediate structure comprising the metallic layer, the dielectric spacer layer, and the stress-absorbing layer;

selectively removing the stress-absorbing layer from the second intermediate structure by dissolving the stress-absorbing layer with acetone to define a third intermediate structure comprising the metallic layer and the dielectric spacer layer; and

transferring the third intermediate structure to a receiver substrate to define the infrared (IR) bandpass filter;

wherein the metallic and dielectric spacer layers comprise nanoholes or nanoposts formed by the array of nanoscale-sized recesses or protuberances of the mold;

wherein the nanoholes or nanoposts of the metallic and dielectric spacer layers are configured to function as quasi three dimensional (quasi 3D) plasmonic metal dielectric hybrid nanostructures.

17 . The method of claim 16 , further comprising fabricating an additional infrared (IR) bandpass filter with the mold.

18 . A method of fabricating an infrared (IR) bandpass filter, the method comprising:

forming metallic and dielectric spacer layers on a mold, the metallic and dielectric spacer layers comprising nanoscale-sized recesses or protuberances defined by the mold;

depositing a stress-absorbing layer on the dielectric spacer layer opposite the mold, wherein the stress-absorbing layer comprises an acrylic;

applying a force to the stress-absorbing layer to peel a first intermediate structure comprising the metallic layer, the dielectric spacer layer, and the stress-absorbing layer from the mold;

selectively removing the stress-absorbing layer from the first intermediate structure with a first solvent configured to dissolve the stress-absorbing layer to define a second intermediate structure comprising the metallic layer and the dielectric spacer layer; and

transferring the second intermediate structure to a receiver substrate to define the infrared (IR) bandpass filter, wherein the recesses or protuberances of the metallic and dielectric spacer layers are configured to function as quasi three dimensional (quasi 3D) plasmonic metal dielectric hybrid nanostructures.