Multilayer Transition-Metal Optical Absorber for Ultra-Wideband Coverage
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Solution Overview
Problem
Existing optical absorbers in the visible-infrared band suffer from narrow absorption bands, low absorption efficiency, complex structures, and high production costs, limiting their applicability and scalability.
Innovation Solution
An ultra-wide band optical absorber based on multilayer transition metal layers, comprising a substrate and a planar multilayer structure with alternating transition metal and dielectric film layers, designed to achieve a thickness of less than 3000 nanometers, ensuring insensitivity to incident angle and polarization, and utilizing materials like titanium, chromium, and magnesium fluoride for enhanced absorption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a Fabry Perot resonator structure is used for optical absorption, then the absorption mechanism is established through electromagnetic wave reflection and interference, but the working bandwidth becomes extremely narrow and the structure becomes sensitive to incident angle and polarization state
Solution Approach 1:
The patent divides the optical absorber into multiple thin film layers (metal layer, dielectric layer, transition metal layer) with specific thicknesses. This segmentation allows each layer to contribute differently to the overall absorption spectrum, enabling broad bandwidth coverage from visible to infrared regions while maintaining structural simplicity and reducing sensitivity to incident angle and polarization state.
2Length of stationary object
If photolithography and sub-wavelength patterned structures are used to design metamaterial absorbers, then the film thickness can be greatly reduced, but the preparation cost increases and the sample area and working bandwidth are limited
Solution Approach 1:
The patent extracts the complex photolithography and sub-wavelength patterning steps from the fabrication process, replacing them with a simple planar multilayer thin film deposition process. This extraction maintains the ability to achieve thin film structures while eliminating the need for expensive and area-limited photolithography techniques, thereby reducing preparation complexity and cost.
Solution Approach 2:
The patent achieves broad bandwidth absorption by carefully controlling the thickness parameters of each layer (metal layer: 50-200 nm, dielectric layer: 100-500 nm, transition metal layer: 10-100 nm) and selecting appropriate materials with specific optical properties. This parameter optimization enables UWB absorption without requiring complex sub-wavelength structures or photolithography processes.
3Reliability
If conventional optical absorbers are designed for specific wavelength bands, then the absorption efficiency can be optimized for that band, but the absorption band remains narrow and cannot cover visible-infrared range
Solution Approach 1:
The patent employs a composite multilayer structure combining metal materials (high reflectivity), dielectric materials (low loss), and transition metal materials (intermediate properties). This composite structure enables the absorber to maintain high absorption efficiency across a broad spectrum from visible to infrared wavelengths, achieving both high reliability and broad adaptability simultaneously.
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 absorber achieves an average absorption rate of over 92% in the visible-near infrared band and over 80% in the mid-infrared band, with flexibility for large-area production and reduced sensitivity to structural errors, eliminating the need for complex photolithography.
Implementation Method 1
When light (i.e., electromagnetic wave) is incident on metal materials, dielectric materials and semiconductor materials, there will be dielectric loss, hysteresis loss and resistance loss, which will make the electromagnetic energy incident on the object be converted into other forms of energy and consumed
Implementation Method 2
When light (i.e., electromagnetic wave) is incident on metal materials, dielectric materials and semiconductor materials, there will be dielectric loss, hysteresis loss and resistance loss
Implementation Method 3
When light (i.e., electromagnetic wave) is incident on metal materials, dielectric materials and semiconductor materials, there will be dielectric loss, hysteresis loss and resistance loss
Implementation Method 4
A common optical absorber structure uses the principle of Fabry Perot resonator, and its optical path is a quarter of the wavelength of electromagnetic wave. Based on the principle of multi-beam interference of multiple reflection of electromagnetic waves, electromagnetic waves interfere with one another so as to eliminate and absorb
Implementation Method 5
Based on the principle of multi-beam interference of multiple reflection of electromagnetic waves, electromagnetic waves interfere with one another so as to eliminate and absorb
Data Source
AI summary
An ultra wide band (UWB) optical absorber based on multilayer transition metal layers is provided, and a working band thereof includes a visible-near infrared band or a mid-infrared band; a high reflecting metal film layer, a transition metal film layer and a dielectric film layer are sequentially stacked on a substrate; the high reflecting metal film layer, multilayer transition metal film layers and the dielectric film layer form a planar multilayer structure. The high reflecting metal film layer is used to prevent light transmission, and the combination of the multilayer transition metal film layers and the dielectric film layer reduces the reflection, thus achieving the effect of efficient optical absorption in UWB. The optical absorber can achieve an average absorptivity of more than 92% in the visible-near infrared band of 400-2500 nm, and an average absorptivity of more than 80% in the mid-infrared band of 3-16 μm.