Fig. 1. Absorption structures: (a) Pixel structure of THz microbolometer focal plane array (FPA); (b) top view of a two-dimensional subwavelength Ti disk array; (c) sectional view of a periodic Ti disk array; (d) absorption structure with a reflection layer; (e) absorption structure with reflection layer and supporting layer; (f) absorption structure illuminated by a plane wave with a rectangular Cartesian coordinate system attached.吸收结构图　(a) 太赫兹微测辐射热计焦平面阵列的探测单元微桥结构; (b)二维亚波长Ti圆盘阵列俯视图; (c) 周期Ti圆盘阵列剖面图; (d) 增加反射层的吸收结构; (e) 增加反射层及支撑层的吸收结构; (f) 直角坐标系下的入射平面波与吸收结构模型

Fig. 2. Material parameters of Ti and Si₃N₄: (a) n_Ti and k_Ti values of Ti at different frequencies; (b) and values of Si₃N₄ at different frequencies. Ti与Si₃N₄的材料参数　(a) Ti在不同频率下的n_Ti与k_Ti值; (b) Si₃N₄在不同频率下的 与 值

Fig. 3. Terahertz wave absorption characteristics of single-layer periodic Ti disk array: (a) Terahertz wave reflection (R), transmission (T), and absorption (A) curves for periodic Ti disk arrays (p = 37 μm, d = 14 μm, t = 10 nm), inset: Reflection (R), transmission (T), and absorption (A) curves for a continuous Ti film with a thickness of 10 nm; (b) terahertz wave absorption at 3.5 THz for Ti disk arrays with different ratios of diameter and period (d/p). 单层周期Ti圆盘阵列的太赫兹波吸收特性　(a)周期Ti圆盘阵列的太赫兹波反射率(R)、透射率(T)与吸收率(A)曲线(p = 37 μm, d = 14 μm, t = 10 nm), 插图为厚度10 nm的连续Ti薄膜的太赫兹波反射率(R)、透射率(T)与吸收率(A)曲线; (b)不同直径周期比(d/p)的Ti圆盘阵列在3.5 THz频率处的太赫兹波吸收率

Fig. 4. Terahertz wave absorption characteristics of periodic Ti disk arrays with resonant cavity reflection layer and supporting layer: (a) Terahertz wave reflection (R), transmission (T) and absorption (A) curves for continuous Ti film and periodic Ti disk arrays with resonant cavity and reflection layer (p = 37 μm, d = 28 μm); (b) terahertz absorption curve for continuous Ti film and periodic Ti disk arrays with different diameters (d) and a supporting layer (p = 37 μm). 带有真空腔、反射层与支撑层的Ti圆盘阵列的太赫兹波吸收特性　(a) 增加真空腔与反射层后连续Ti薄膜与Ti圆盘阵列(p = 37 μm, d = 28 μm)在不同频率下的太赫兹波反射率、透过率与吸收率; (b) 增加支撑层后连续Ti薄膜与不同直径(d)的Ti圆盘阵列(p = 37 μm)在不同频率下的太赫兹波吸收率

Fig. 5. Terahertz wave absorption characteristics of periodic Ti disk arrays with different thicknesses of supporting layer and Ti disks: (a) Terahertz absorption at different frequencies for absorption structures with different thicknesses (h) of Si₃N₄ support layers (p = 37 μm, d = 34 μm, t = 10 nm); (b) terahertz absorption at different frequencies for absorption structures with different thicknesses (t) of Ti disks; Inset: Peak absorption rate at 3.5 THz for absorbing structures with different thicknesses (t) of Ti disks (p = 37 μm, d = 34 μm). 不同Si₃N₄支撑层厚度与Ti圆盘厚度的吸收结构的太赫兹波吸收特性　(a)不同Si₃N₄支撑层厚度(h)的吸收结构在不同频率下的太赫兹波吸收率(p = 37 μm, d = 34 μm, t = 10 nm); (b)不同Ti圆盘厚度(t)的吸收结构在不同频率下的太赫兹波吸收率, 插图为不同Ti圆盘厚度(t)的吸收结构在3.5 THz下的峰值吸收率(p = 37 μm, d = 34 μm)

Fig. 6. Electric field distribution of the absorption structure at the resonance absorption frequency (3.5 THz): (a) Electric field distribution in the yz plane; (b) electric field distribution in the xy plane (p = 37 μm, d = 34 μm, t = 40 nm). 共振吸收频率(3.5 THz)下吸收结构的电场分布　(a) yz平面上吸收结构的电场分布; (b) xy平面上吸收结构的电场分布(p = 37 μm, d = 34 μm, t = 40 nm)