钛圆盘阵列增强微测辐射热计太赫兹波吸收特性  

Absorption enhancement of terahertz wave in microbolometers by titanium disk array

作　　者：牛青辰 苟君[1] 王军[1] 蒋亚东[1] Niu Qing-Chen;Gou Jun;Wang Jun;Jiang Ya-Dong(State Key Laboratory of Electronic Thin Films and Integrated Devices, University of Electronic Science and Technology of China, Chengdu 610054, China)

机构地区：[1]电子科技大学电子薄膜与集成器件国家重点实验室

出　　处：《物理学报》2019年第20期292-300,共9页Acta Physica Sinica

基　　金：国家自然科学基金(批准号:61875031);国家自然科学基金创新研究群体科学基金(批准号:61421002)资助的课题~~

摘　　要：提出一种集成在微桥结构中的二维亚波长周期钛(Ti)金属圆盘阵列结构,以增强太赫兹微测辐射热计的吸收率.基于严格耦合波分析方法,建立吸收结构模型,研究了不同结构的Ti圆盘阵列及其在微桥阵列结构中的太赫兹波吸收特性.周期Ti圆盘阵列结构降低了金属的表面等离子体频率,在太赫兹波段激发伪表面等离子体激元并实现共振增强吸收.共振吸收频率由周期、直径等Ti圆盘阵列的结构参数决定,圆盘厚度则对太赫兹波吸收率有重要影响,微桥结构中的谐振腔结构可降低共振频率并增强耦合效率.设计的微桥探测结构以较小的Ti圆盘阵列周期(37μm)实现突破衍射极限的太赫兹波约束,在3.5 THz (波长85.7μm)实现接近90%的太赫兹波吸收率,满足太赫兹微测辐射热计小尺寸、高吸收及工艺兼容的要求.In this paper, a two-dimensional subwavelength periodic titanium(Ti) disk array integrated in microbridge structure is proposed to enhance the absorption of terahertz(THz) microbolometer. Based on the rigorous coupled wave analysis(RCWA) method, THz absorption characteristics of Ti disk arrays with different structure parameters in micro-bridge structure arrays are studied. Periodic disk array structure reduces the surface plasmon frequency of Ti, excites the spoof surface plasmons in the THz band and leads to resonance enhanced absorption. The resonance absorption frequency is determined by the structural parameters of Ti disk array including period and diameter while the absorption rate of THz wave is greatly affected by the thickness of Ti disks. The resonant cavity in micro-bridge structure can reduce the resonance frequency and enhance the coupling efficiency. The micro-bridge structure designed in this paper breaks the diffraction limit and traps the THz wave with a small period(37 μm). An absorption of nearly 90% is achieved at 3.5 THz. The structure meets the requirements of small size, high absorption and good process compatibility of the THz microbolometer.

关 键 词：太赫兹 微测辐射热计 伪表面等离子体激元 严格耦合波分析 

分 类 号：O441.4[理学—电磁学]