3-5 [mu] m medium-wave infrared broadband perfect absorber

The invention relates to an embedded absorber which is mainly used for absorbing light with the wavelength in the spectral range of 3 microns to 5 microns. The absorber comprises a plurality of embedded absorption units, and each embedded absorption unit comprises a metal titanium bottom layer located on the bottom layer, and the thickness of the metal titanium bottom layer is t metal 2 = 0.2 mu m; the thickness of the silicon dielectric layer is as follows: t dielectric 1 is 0.5-0.65 [mu] m; the circular ring is positioned on the middle layer and is made of a metal material, and the thickness of the circular ring is that tmetal 1 is equal to 0.05-0.2 mu m; the aluminum oxide dielectric layer is positioned on the surface layer, and the thickness of the aluminum oxide dielectric layer is as follows: t dielectric 2 is 0.5-0.8 mu m; the inner and outer radiuses of the circular ring are r metal 1 and R metal 1 respectively, the period is p, and the distance between the circular ring and the substrate is d metal 1