Thermal barrier effect analysis of magnesium-fluoride conformal dome and the experimental validation

Tianyi, 张天翼 Zhang; Qun, 魏群 Wei; Chao, 王超 Wang; Linyao, 虞林瑶 Yu; Ruifei, 朱瑞飞 Zhu

doi:10.3788/m0001820164502.220001

Cited by 2 publications

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“…Therefore, it remains a great challenge to implement infrared windows with ultrahigh transmittance and make them more adaptable to extremely harsh environments. Magnesium fluoride (MgF 2 ) is frequently chosen as an alternative material for infrared windows due to its high thermal, mechanical, and chemical stability, as well as its high transmittance and low absorption in the mid-wave infrared broadband. − However, MgF 2 windows have 6–7% infrared reflection from the surface and exhibit poor hydrophobic and wide angle of incidence properties, which limit their application in harsh environments. In nature, dragonflies are famous for not only their wonderful flying skills but also their excellent antireflectivity and superhydrophobicity due to the special structures on their wings. − Dragonfly provides great inspiration for the fabrication of anti-reflective surfaces with microstructures array.…”

Section: Introductionmentioning

confidence: 99%

Bioinspired Near-Full Transmittance MgF₂ Window for Infrared Detection in Extremely Complex Environments

Ding

Liu

Wang

et al. 2023

ACS Appl. Mater. Interfaces

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Due to the extreme complexity of the anti-reflective subwavelength structure (ASS) parameters and the drastic limitation of Gaussian beam manufacturing accuracy, it remains a great challenge to manufacture ASS with ultrahigh transmittance on the surface of infrared window materials (such as magnesium fluoride (MgF2)) directly by femtosecond laser. Here, a design, manufacturing, and characterization method that can produce an ultrahigh-performance infrared window by femtosecond laser Bessel beam is proposed. Inspired by the excellent anti-reflective and hydrophobic properties of the special structure of dragonfly wings, a similar structural pattern with grid-distributed truncated cones is designed and optimized for its corresponding parameters to achieve near-full transmittance. The desired submicron structures are successfully fabricated by a Bessel beam after effectively shaping the beam. As a practical application, the bioinspired ASS is manufactured on the surface of MgF2, achieving an ultrahigh transmittance of 99.896% in the broadband of 3–5 μm, ultrawide angle of incidence (over 70% at 75° incidence), and good hydrophobicity with a water contact angle of 99.805°. Results from infrared thermal imaging experiments show that the ultrahigh-transmittance MgF2 window has superior image acquisition and anti-interference performance (3.9–8.6% image contrast enhancement and more accurate image edge recognition) in an environment with multiple interfering factors, which may play a significant role in facilitating applications of infrared thermal imaging technologies in extremely complex environments.

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Section: Introductionmentioning

confidence: 99%

Bioinspired Near-Full Transmittance MgF₂ Window for Infrared Detection in Extremely Complex Environments

Ding

Liu

Wang

et al. 2023

ACS Appl. Mater. Interfaces

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Progressive Nonuniformity Correction for Aero-Optical Thermal Radiation Images via Bilateral Filtering and Bézier Surface Fitting

Liu

Xiong

et al. 2023

IEEE Photonics J.

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When a high-speed aircraft flies in the atmosphere, the imaging window is subjected to airflow friction, the kinetic energy of the airflow is converted into thermal energy, which makes the surface temperature of the imaging window rise unevenly, the imaging quality is significantly reduced, called aerooptical thermal radiation effects. The continuously increasing nonuniform thermal radiation bias field is not conducive to the precise identification of the target. To remove the bias field in degraded infrared images, this paper proposes a progressive nonuniformity correction method. First, we establish a progressive thermal radiation effects correction model to estimate the thermal radiation bias field based on bilateral filtering and Bézier surface fitting. Then, to avoid overfitting the bias field, the degree of Bézier surface is reduced progressively during the iterative process. Finally, according to the properties of the heat transfer of the aero-optical thermal radiation effects, a gradient orientation prior is imposed for both the thermal radiation bias field and the latent clear image. experiments on simulated degraded images and real degraded IR images show that our method can reduce the thermal radiation effects residual compared with the current aero-optical thermal radiation effects correction methods. The code will be publicly available upon acceptance.

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Thermal barrier effect analysis of magnesium-fluoride conformal dome and the experimental validation

Cited by 2 publications

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Bioinspired Near-Full Transmittance MgF₂ Window for Infrared Detection in Extremely Complex Environments

Bioinspired Near-Full Transmittance MgF₂ Window for Infrared Detection in Extremely Complex Environments

Progressive Nonuniformity Correction for Aero-Optical Thermal Radiation Images via Bilateral Filtering and Bézier Surface Fitting

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Thermal barrier effect analysis of magnesium-fluoride conformal dome and the experimental validation

Cited by 2 publications

References 0 publications

Bioinspired Near-Full Transmittance MgF2 Window for Infrared Detection in Extremely Complex Environments

Bioinspired Near-Full Transmittance MgF2 Window for Infrared Detection in Extremely Complex Environments

Progressive Nonuniformity Correction for Aero-Optical Thermal Radiation Images via Bilateral Filtering and Bézier Surface Fitting

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Product

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Bioinspired Near-Full Transmittance MgF₂ Window for Infrared Detection in Extremely Complex Environments

Bioinspired Near-Full Transmittance MgF₂ Window for Infrared Detection in Extremely Complex Environments