A metamaterial perfect absorber for visible-near infrared broadband was proposed. The structure consists of four layers including reflective metal Ti layer, dielectric SiO2 layer, thin Ti layer, and the top single-sized Ti cylinder, which is named the generalized M/I/M absorber. We numerically studied the absorptivity of the absorber and achieved nearly perfect absorption via optimizing the structural parameters. Our Theoretical results show that (1) the maximum absorptivity in the high absorption window is as high as 99.96% over the wavelength range from 350~1400nm and the average absorptivity across the broadband was 98.21%. (2) this structure is insensitive to the incident angle of electromagnetic wave. We hope that such a device could be applied in solar energy absorption, thermal electronic equipment and perfect cloaking.
We propose that dual-band coherent perfect absorption in the infrared can be achieved in a metasurface, which contains periodical symmetrically patterned elliptical graphene array on both sides of the silicon dioxide film. The physical mechanism of dual-band absorption is that the major and minor axes of the elliptical graphene disk have different widths and can produce resonances at different frequencies. Based on the independent resonances, the asymmetrically patterned metasurface can separately absorb light of different frequencies for TE and TM polarizations, which is useful to detect the polarization of incident light. In addition, the coherent absorptivity of each peak can be tuned by phase modulation and the dual-band absorption frequencies can be flexibly adjusted by changing the Fermi level of the graphene via chemical or electronic doping. Therefore, our proposed metasurface can achieve the double modulation for both absorption frequency and absorptivity, which make it a good candidate for optical switch and absorption modulator.
In this paper, we propose a frequency tunable metamaterial perfect absorber in the THz region based on graphene. The unit cell consists of a periodically patterned graphene cross-ring resonator and a gold film separated by a dielectric spacer. The simulation results demonstrate that the maximum value of absorption is 99.9% at 4.7 THz. By controlling the graphene conductivity, the frequency tunable characteristics can be achieved in this metamaterial absorber. When varying the diameter of the ring or the length of the cross, we find that resonance absorption frequency will significantly shifts. Moreover, the metamaterial absorber possesses the polarization-insensitive and a wide range of the incident angles up to 70° for both TE and TM polarization. Our absorber can be used in some practical applications due to its excellent absorption and simple structure.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
INSTITUTIONAL Select your institution to access the SPIE Digital Library.
PERSONAL Sign in with your SPIE account to access your personal subscriptions or to use specific features such as save to my library, sign up for alerts, save searches, etc.