Two-dimensional metallic broadband absorbers on a SiO(2)/Ag/Si substrate were experimentally studied. The absorptivity of such structure can be increased by tailoring the ratio of disk size to the unit cell area. The metallic disk exhibits a localized surface plasmon polariton (LSPP) mode for both TE and TM polarizations. A broadband thermal emitter can be realized because the LSPP mode is independent of the periodicities. By manipulating the ratios and disk sizes, a high-performance, wide-angle, polarization-independent dual band absorber was experimentally achieved. The results demonstrated a substantial flexibility in absorber designs for applications in thermal photovoltaics, sensors, and camouflage.

It is shown that the metallic disk structure can be used as an efficient narrow-band thermal emitter in the IR region. The absorption spectra of such structure are investigated both theoretically and experimentally. Calculations of thermal radiation properties of the metallic disk show that the metallic disk is a perfect emitter at a specific wavelength, which can be tuned by varying the diameter of the disk. The metallic disk exhibits only one significant localized surface plasmon polariton (LSPP) mode for both TM and TE polarizations simultaneously. The LSPP mode can be tuned by either varying the disk diameter or the spacer (made of SiO2).

In this paper, we show that a localized surface plasmon polariton in a plasmonic sandwich structure made of a (metal elliptical disc)/(dielectric spacer)/(metal film) can be used as an efficient angle-independent polarizer in the mid-infrared wavelength regime. The elliptical disc structure is characterized by using a Fourier transform infrared spectrometer and simulated via the rigorous coupled wave analysis (RCWA) method. For the optimum design, we can obtain a degree of polarization of 99% both experimentally and theoretically. A high extinction ratio between 20 and 40 dB can be obtained by changing the axis ratio of the elliptical disc between 0.65 and 0.85. The wavelength of polarized light can be tuned in a wide range by changing the structural parameters. The plasmon-polariton band structures of the elliptical disc structure for both TM and TE polarizations are also studied theoretically via RCWA.

In this study, the localized surface plasmon polariton (LSPP) band gap of an Ag/SiO(2)/Ag asymmetric T-shaped periodical structure is demonstrated and characterized. The Ag/SiO(2)/Ag asymmetric T-shaped periodical structure was designed and fabricated to exhibit the LSPP modes in an infrared wavelength regime, and its band gap can be manipulated through the structural geometry. The LSPP band gap was observed experimentally with the absorbance spectra and its angle dependence characterized with different incident angles. Such a T-shaped structure with a LSPP band gap can be widely exploited in various applications, such as emitters and sensors.