title: Wavelength-tunable perfect absorber based on guided-mode resonances.
abstract: We numerically investigate the triple-band perfect absorption in a metal-insulator-metal structure. The absorption peak from the TE-polarized guided-mode resonance (GMR) is highly sensitive to the incident angle. Thus a wavelength-tunable perfect absorber (PA) based on the TE GMR is proposed for the first time. By the precise control of the incident angle, the ∼5  nm narrowband perfect absorber can be modulated linearly about 3 nm/° in our structure. For single frequency light, the intensity tunability of the absorption between 6.2%-99.27% is realized only by changing the incident angle of 5°. The further study focused on TM polarization confirms the possibility to realize a polarization-independent wavelength-tunable PA. Such a PA possesses potential for applications in absorption filter, thermal emitter, surface-enhanced Raman scattering, biosensing, and nonlinear optics.
authors.forename: Si
authors.initials: S
authors.lastname: Zhang
authors.forename: Yufei
authors.initials: Y
authors.lastname: Wang
authors.forename: Shaohua
authors.initials: S
authors.lastname: Wang
authors.forename: Wanhua
authors.initials: W
authors.lastname: Zheng