基于超材料吸收器的非制冷微红外热探测器

Uncooled Micro-infrared Heat Detector Based on Metamaterial Absorber

摘要:

基于超材料的红外吸收器具有光谱范围广、响应快、灵敏度高等优点,在军事和生活中应用广泛。本文研究了一种叠层结构的超材料吸收器,该吸收器利用光学超材料的局域场增强效应,并结合热释电材料的温度敏感特性,可实现中红外波段的探测。在此基础上,设计了一种可在3~15 μm范围内调制峰值波长的超材料吸收器(覆盖大气窗口(8~14 μm)),其吸收率可达99.9%,带宽范围为0.2~1 μm。通过调节热探测器中的热分布,本文所研制的吸收器在与类似研究工作相比,温度提升了约21倍。通过多物理场模型,对吸收器与新型热释电材料(LiTaO3)耦合结构的电磁场特性和热学特性进行分析。结果表明,当探测器的阵列为5×5时,探测器稳态温度的变化量为0.311 K。本文所设计的超材料吸收器具有显著提高器件的热响应和稳定温度的优势,适用于大规模像元级非制冷中远红外波段的热成像与传感应用。

Abstract:

Infrared absorbers based on metamaterials are widely used in military and daily life, due to their superior characteristics of wide spectral range, fast response, and high sensitivity, etc. In this study, a metamaterial absorber with a stacked structure is investigated, which utilizes the local field enhancement effect of optical metamaterials and combines the temperature-sensitive properties of pyroelectric materials to achieve mid-infrared detection. Based on this, a metamaterial absorber (covering the atmospheric window (8~14 μm)) that can modulate the peak wavelength in the range of 3~15 μm was designed, with an absorbance rate of 99.9% and a bandwidth range of 0.2~1 μm. The distribution of the detector heat can be adjusted by the absorber, and the temperature is elevated by a factor of about 21 compared to similar work at the same size. A multi-physics analysis method is used to analyze the electromagnetic field characteristics and thermal properties of the absorber and pyroelectric material (LiTaO3) coupled structure. The results show that when the array of detectors is 5×5, the temperature rise of the detector steady-state temperature is 0.311 K. The designed metamaterial absorber can significantly improve the thermal response and stabilization temperature of the device, and it is applicable to thermal imaging and sensing in uncooled Mid-Infrared and Far-Infrared wavelengths at the large-scale image element level.