Hyperbolic Metamaterial Fabrication Using Silver and BST

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Solution Overview

Problem

Existing hyperbolic metamaterials face challenges in achieving better transmission and lower loss from reflection and absorption, particularly due to high dielectric loss in silver and changes in dielectric function post-deposition of materials like titanium dioxide.

Innovation Solution

A method involving the deposition of silver and barium strontium titanate (BST) layers, with annealing above the Curie temperature, to create a hyperbolic metamaterial with controlled refractive index, utilizing a fill fraction calculation to optimize the thickness and composition of layers for reduced loss and enhanced transmission.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If thicker multilayer structure is formed to improve hyperbolic response, then simulation results improve, but transmission loss increases

Engineering Contradiction:

Improvehyperbolic response accuracyVSAvoidtransmission loss

Core Design Contradiction:

Manufacturing precisionVSLoss of energy

Solution Approach 1:

The patent changes the dielectric material parameter to ferroelectric materials with inherently high dielectric function that is maintained after deposition. This allows achieving the required hyperbolic response with thinner layers, thereby improving transmission while maintaining simulation accuracy.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent creates a simplified version of the multilayer structure by using materials with higher and more stable dielectric function. This allows achieving the same hyperbolic response with fewer or thinner layers, effectively 'copying' the desired optical behavior with reduced structural complexity and thickness.

Inventive Principle:

Principle #26Copying

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

The method effectively reduces reflection and absorption losses while maintaining high transmission, achieving unique refractive indices not found in nature, suitable for applications requiring specific optical properties.

Implementation Method 1

the substrate is annealed at a temperature that is above the Curie temperature of the BST material formed with BTO and STO

Methodology Applied

Scientific EffectAnnealing: Annealing

Implementation Method 2

annealed at a temperature that is above the Curie temperature of the BST material

Methodology Applied

Scientific EffectCurie temperature transition: Curie Point (piezoelectric)

Implementation Method 3

After a first layer of silver has been deposited on a substrate, a layer of the BST is deposited on the first layer of silver. Next, a second layer of silver is deposited on the BST layer

Methodology Applied

Scientific EffectPhysical vapor deposition: Physical Vapour Deposition

Data Source

PatentUS11329389B2Method for fabricating a hyperbolic metamaterial having a near-zero refractive index in the optical regime

Publication Date: 2022.05.10 THE BOARD OF REGENTSOF THEUNIV OF TEXAS SYST

AI summary

A method for fabricating a hyperbolic metamaterial coating having a near-zero refractive index is disclosed. The direction of propagating light changes by means of generating subwavelength structures that alter the coatings permittivity and permeability. The coating can be deposited on lenses or incorporated into optical devices. This type of metamaterial can be utilized to direct light towards sensors or to collect light efficiently.