摘要： In this paper, we theoretically design and numerically verify a broadband plasmonic absorber that works continuously in ultraviolet to near-infrared region. Different from the traditional metal-insulator-metal (MIM) three-layer structure, our perfect absorber is based on insulator-metal-insulator-metal (IMIM) four-layer structure. This perfect absorber owns a 280 nm ultra-thin thickness, a configuration of refractory metal titanium nitride and high-melting-point insulator silica equips it with strong thermal stability. The novel titanium nitride ring-square array layer combines the absorption of different wavelength bands so that the absorber can achieves a continuous absorption of more than 90% from wavelength 200–1200 nm. Using Finite-difference time-domain (FDTD) method, we get a calculated average absorption rate as 94.85%, which includes a 99.40% maximum absorption at wavelength 270 nm and a 90.30% minimum absorption at 390 nm. In addition, this perfect absorber demonstrates polarization independence under normal incidence and large incident angle insensitivity under oblique incidence, which has significant application potentials in many areas such as solar energy collection, photothermal conversion, and invisibility cloak.