title: Surface-plasmon mediated total absorption of light into silicon.
abstract: We report surface-plasmon mediated total absorption of light into a silicon substrate. For an Au grating on Si, we experimentally show that a surface-plasmon polariton (SPP) excited on the air/Au interface leads to total absorption with a rate nearly 10 times larger than the ohmic damping rate of collectively oscillating free electrons in the Au film. Rigorous numerical simulations show that the SPP resonantly enhances forward diffraction of light to multiple orders of lossy waves in the Si substrate with reflection and ohmic absorption in the Au film being negligible. The measured reflection and phase spectra reveal a quantitative relation between the peak absorbance and the associated reflection phase change, implying a resonant interference contribution to this effect. An analytic model of a dissipative quasi-bound resonator provides a general formula for the resonant absorbance-phase relation in excellent agreement with the experimental results.
authors: Department of Physics, Hanyang University, Seoul 133-791, South Korea.
authors: Jae Woong
authors: JW
authors: Yoon
authors: Woo Jae
authors: WJ
authors: Park
authors: Kyu Jin
authors: KJ
authors: Lee
authors: Seok Ho
authors: SH
authors: Song
authors: Robert
authors: R
authors: Magnusson
mesh_terms: D000042:Absorption; D006046:Gold; D007368:Interferometry / Q000379:methods; D008027:Light; D015233:Models, Statistical; D055095:Optics and Photonics; D009991:Oscillometry / Q000379:methods; D012825:Silicon / Q000737:chemistry*; D020349:Surface Plasmon Resonance / Q000379:methods*
chemical_list: D006046:Gold; D012825:Silicon