Optical elements based on polymeric structures incorporating inorganic materials
The present disclosure relates to display systems and, more particularly, to augmented reality display systems. In one aspect, a method of fabricating an optical element includes providing a substrate having a first refractive index and transparent in the visible spectrum. The method additionally includes forming on the substrate periodically repeating polymer structures. The method further includes exposing the substrate to a metal precursor followed by an oxidizing precursor. Exposing the substrate is performed under a pressure and at a temperature such that an inorganic material comprising the metal of the metal precursor is incorporated into the periodically repeating polymer structures, thereby forming a pattern of periodically repeating optical structures configured to diffract visible light. The optical structures have a second refractive index greater than the first refractive index.
1. A method of fabricating an optical element, comprising:
providing a substrate having a first refractive index, the substrate being transparent in the visible spectrum;
forming, on the substrate, periodically repeating polymer structures having an initial refractive index;
performing a first atomic layer deposition step to form a molecular layer of a first precursor on the periodically repeating polymer structures;
performing a second atomic layer deposition step using a second precursor, which is different from the first precursor, to form a layer of target material on the periodically repeating polymer structures, wherein the periodically repeating polymer structures comprising the layer of target material are configured to diffract visible light and have a second refractive index greater than the first refractive index and greater than the initial refractive index,
wherein performing the first atomic layer deposition step occurs in a reaction chamber, and wherein the method comprises purging, subsequent to performing the first atomic layer deposition step, the reaction chamber of the first precursor,
wherein performing the second atomic layer deposition step occurs in the reaction chamber, and wherein the method comprises purging, subsequent to performing the second atomic layer deposition step, the reaction chamber of the second precursor, and
wherein performing the first atomic layer deposition step, purging of the first precursor, performing the second atomic layer deposition step, and purging of the second precursor constitute a growth cycle, and the method comprises repeatedly performing the growth cycle until a predetermined thickness of the layer of target material is achieved; and
controlling, during the growth cycle, a purge time, a total pressure, a partial pressure, and/or a substrate temperature to control diffusion of the first precursor and the second precursor into the periodically repeating polymer structures.
2. The method of claim 1 , wherein the first precursor comprises a metal precursor.
3. The method of claim 2 , wherein the metal precursor comprises a transition metal.
4. The method of claim 3 , wherein the transition metal comprises Al, Zn, Zr, Hf, Ti, or Ta.
5. The method of claim 2 , wherein the metal precursor comprises aluminum oxide, zinc oxide, zirconium oxide, hafnium oxide, titanium oxide, tantalum oxide, or combinations thereof.
6. The method of claim 2 , wherein the metal precursor comprises a halide compound.
7. The method of claim 2 , wherein the metal precursor comprises an alkyl compound.
8. The method of claim 2 , wherein the metal precursor comprises an alkoxide compound.
9. The method of claim 1 , wherein the second precursor comprises an oxidizing precursor.
10. The method of claim 9 , wherein the oxidizing precursor comprises molecular oxygen, ozone, water, hydrogen peroxide, nitrous oxide, ammonia, or combinations thereof.
11. The method of claim 10 , wherein the plurality of functional groups comprises a carbonyl group, a hydroxyl group or a pyridine group.
12. The method of claim 1 , wherein the periodically repeating polymer structures comprise a plurality of functional groups configured to react with the first precursor to form an inorganic material.
13. The method of claim 1 , wherein at least a portion of the first precursor diffuses into the periodically repeating polymer structures and reacts with a functional group of the periodically repeating polymer structures.
14. The method of claim 13 , wherein at least a portion of the second precursor diffuses into the periodically repeating polymer structures and reacts with the first precursor to form the target material.
15. The method of claim 14 , wherein the target material is an inorganic material.
16. The method of claim 1 , wherein at least a portion of the target material diffuses into the periodically repeating polymer structures after being formed.