Fig. 1. Schematic diagram of device structure：（a） Schematic diagram of thermal conduction of common "umbrella" double-layer uncooled IR detector structure； （b） Schematic diagram of the thermal conduction of the IMIAM cavity metasurface uncooled IR detector structure； （c） Stereogram of common "umbrella" double-layer uncooled IR detector； （d） Stereogram of a "hole" type IMIAM metasurface uncooled IR detector； （e） Stereogram of the "antenna" type IMIAM metasurface uncooled IR detector； （f） Top view of the "hole" type IMIAM metasurface structure （where C₁ is a cube-shaped "hole" type and C₂ is a cylindrical "hole" type）； （g） Top view of the "antenna" type IMIAM metasurface structure （where S₁ is a cube-shaped "antenna" type and S₂ is a cylindrical "antenna" type）； （h） Cross-sectional view of the IMIAM cavity-type metasurface uncooled IR detector； （i） Cross-sectional view of the IMIAM cavity-type metasurface structure

Fig. 2. Under the given condition of h₂，Graph of the absorptivity of the detector operating band as a function of h₁：（a）h₂=1.5 μm；（b）h₂=2 μm；（c）h₂=2.5 μm；（d）h₂=3 μm；（e）h₂=3.5 μm

Fig. 3. The absorption curve of the detector with the thickness of each layer of the metasurface structure：（a） d₁； （b） d₂； （c） d₃； （d） d₄

Fig. 4. Detector absorption curve when the parameters of the superstructure of SiN_x/Ti/SiN_x change：（a） the absorption curve of the detector with n change when the C₁ structure is m=1.5 μm； （b） The absorption curve of the detector with n when the C₂ structure is m=1.5 μm； （c） The absorption curve of the detector with n when the C₃ structure is m=1.5 μm； （d） The absorption curve of the detector with n when the C₄ structure is m=1.5 μm； （e） The absorption curve of the detector with m when the C₁ structure is n/m=0.53； （f） Detector absorption curves under different structures （f-1 is the optimal C₁ structure； f-2 is the optimal C₂ structure； f-3 is the optimal S₁ structure； f-4 is the optimal S₂ structure； f-5 is the S₁ structure when multi-pixel is optimal； The f-6 is a traditional uncooled IR detector structure）

Fig. 5. Top view （left） and cross-section view （right） of the process preparation process：（a） Micro-bridge structure construction； （b） Preparation of photosensitive layers； （c） Electrode connection； （d） Cavity-type metasurface preparation

Fig. 6. Confocal microscopy image （corresponding to Fig. 5）

Fig. 7. Comparison of simulated and experimental absorption spectra（where simulation1 corresponds to f-3 in Figure 4； simulation2 corresponds to f-5 in Figure 4.）