Triple band diamond-shaped polarization insensitive plasmonic nano emitter for thermal camouflage and radiative cooling
At a Glance
Section titled âAt a Glanceâ| Metadata | Details |
|---|---|
| Publication Date | 2024-05-13 |
| Journal | Optical and Quantum Electronics |
| Authors | Atıf Kerem Ćanlı, Timuçin Emre Tabaru, Veli Tayfun Kılıç |
| Institutions | Sivas State Hospital, Abdullah GĂŒl University |
| Citations | 8 |
| Analysis | Full AI Review Included |
Executive Summary
Section titled âExecutive SummaryâThis research introduces a novel Metal-Insulator-Metal (MIM) Diamond-shaped Nano Emitter (DNE) optimized for simultaneous thermal camouflage and radiative cooling across the infrared spectrum.
- Triple-Band Functionality: The DNE achieves high absorption/emission across three critical atmospheric windows: Short-Wave Infrared (SWIR), Mid-Wave Infrared (MWIR), and Non-Transmissive Infrared Range (NTIR).
- High Absorption Peaks: Four narrow resonance peaks are observed in SWIR (2.20, 2.54, 2.99 ”m) and MWIR (3.99 ”m), all exhibiting >90% absorption.
- Radiative Cooling Performance: A wide absorption band in the NTIR (5-8 ”m) achieves >97% absorption, providing strong cooling characteristics compatible with camouflage requirements.
- Thermal Camouflage: The structure maintains low average emissivity in critical detection bands (MWIR: 0.17; LWIR: 0.32) across temperatures up to 1000 K, significantly reducing thermal signatures compared to a blackbody emitter.
- Design and Materials: The structure uses a simple, polarization-insensitive design (in-plane symmetric) based on CMOS-compatible materials (Ag grating/substrate and Si3N4 dielectric), supporting potential low-cost fabrication.
- Mechanism: High absorption is achieved through effective impedance matching (near-zero reflection) and physical mechanisms including Surface Plasmon Polaritons (SPPs) and Fabry-Perot modes.
Technical Specifications
Section titled âTechnical Specificationsâ| Parameter | Value | Unit | Context |
|---|---|---|---|
| Structure Type | MIM Metamaterial | N/A | Diamond-Shaped Nano Emitter (DNE) |
| Grating/Substrate Material | Silver (Ag) | N/A | Plasmonic metal |
| Dielectric Material | Silicon Nitride (Si3N4) | N/A | Insulator layer |
| Grating Thickness (t) | 20 | nm | Optimized dimension |
| Grating Side Length (N) | 900 | nm | Optimized dimension |
| Dielectric Height (H2) | 350 | nm | Optimized dimension |
| Periodicity (P) | 2090 | nm | Optimized dimension (x and y axes) |
| SWIR Peak 1 (lambda1) | 2.20 | ”m | Absorption > 90% |
| MWIR Peak 4 (lambda4) | 3.99 | ”m | Absorption > 90% |
| NTIR Peak 5 (lambda5) | 7.4 | ”m | Absorption > 97% |
| Average Emissivity (MWIR) | 0.17 | N/A | 3-5 ”m range (Camouflage) |
| Average Emissivity (LWIR) | 0.32 | N/A | 8-12 ”m range (Camouflage) |
| Average Emissivity (NTIR) | 0.44 | N/A | 5-8 ”m range (Cooling) |
| Effective Impedance of Air | 377 | Ω | Target impedance for perfect absorption |
| Operating Temperature Range | 300 to 1000 | K | Tested range for signature stability |
Key Methodologies
Section titled âKey MethodologiesâThe DNE performance was validated and optimized using 3D Finite-Difference Time-Domain (FDTD) simulations.
- Simulation Setup: The MIM structure (Ag/Si3N4/Ag) was modeled using 3D FDTD. Boundary conditions were set as Periodic in the x and y axes and PML (Perfect Match Layer) in the z-axis.
- Illumination Source: A TM polarized plane wave light source was placed above the structure, sweeping wavelengths between 1 ”m and 12 ”m.
- Optimization Process:
- Initial single-parameter sweeps were conducted for grating thickness (t), grating side length (N), and periodicity (P) to identify the general effect of each parameter on resonance peak position and amplitude.
- Dual-parameter sweeps (e.g., thickness vs. periodicity) were subsequently performed to fine-tune dimensions and maximize absorption amplitude across the five target resonance peaks (lambda1 to lambda5).
- Absorption and Impedance Calculation: Reflectance (R) and transmission (T) were monitored. Absorption (A) was calculated as A = 1 - R, assuming T â 0 due to the metallic substrate. Effective impedance (Zeff) was derived from S-parameters (S11) to confirm matching with the surrounding air (377 Ω) at resonance wavelengths.
- Physical Mechanism Analysis: Electric (E) field and Magnetic (H) field distribution plots were extracted from the simulations (top and front views) at each resonance wavelength to confirm the excitation of Surface Plasmon Polaritons (SPPs) and Fabry-Perot modes.
- Thermal Emission Modeling: Total thermal emission (TE) was calculated using Planckâs law (BBE) and the effective emissivity (epsiloneff) derived from the absorption spectrum, demonstrating signature reduction relative to a blackbody at 300 K and higher temperatures.
Commercial Applications
Section titled âCommercial ApplicationsâThis technology provides advanced solutions for thermal management and stealth in high-performance engineering systems.
- Military and Defense:
- Thermal Camouflage: Effective suppression of thermal signatures in the MWIR and LWIR atmospheric windows for aircraft, ground vehicles, and naval assets.
- Stealth Technology: Provides a tunable, high-efficiency solution for deceiving IR detection systems by controlling thermal emission profiles.
- Aerospace and UAVs:
- Thermal Management: Integration into UAVs and satellites where lightweight, thin films are required for passive radiative cooling (using the NTIR band) while maintaining low observability.
- Infrared Optoelectronics:
- Selective Emitters/Absorbers: Used in specialized IR sensors, detectors, and filters requiring precise spectral control over absorption and emission characteristics across multiple bands (SWIR, MWIR, NTIR).
- Energy and HVAC:
- Passive Cooling Systems: Implementation in building materials or infrastructure for efficient, passive daytime and nighttime radiative cooling, leveraging the high NTIR emission band.
- Manufacturing and Fabrication:
- CMOS-Compatible Metamaterials: The use of Ag and Si3N4 and simple geometry supports potential scalability and lower production costs using standard lithography techniques for large-area metamaterial films.
View Original Abstract
Abstract This study proposes the design of a novel Metal-Insulator-Metal (MIM) nano-infrared emitter that uses a unique diamond-shaped grating to achieve selective infrared absorption. Diamond-shaped nano emitter (DNE) structure exhibits four narrow resonant peaks within key absorption windows such as short-wave infrared (SWIR) mid-wave infrared (MWIR), alongside with a wide absorption band in the Non-Transmissive Infrared Range (NTIR) for thermal camouflage applications compatible with radiative cooling. Moreover, the proposed DNE is polarization insensitive as it has an in-plane symmetric design. Using the 3D Finite-Difference Time-Domain (FDTD) simulations, we demonstrate the nanoantennaâs superior performance characterized by its high absorption rates and tuned effective impedance matching. As of our knowledge, the findings suggest that this is the first time that a MIM structure achieved multiple narrow resonance peaks, located in SWIR and MWIR simultaneously, with a wide absorption range in NTIR. Represented DNE stands as a significant innovation in the field of stealth technology, providing a tunable, high-efficiency solution for managing and controlling thermal emissions across diverse applications.