Figure 2: Optical properties of ultrathin planar absorbers based on small band gap semiconductors.

(a) Calculated and (c) measured angular reflectivities of the 18 nm Ge/Ag structure for TE polarization and the (b) calculated and (d) measured results for TM polarization. Calculated angular reflectivities of 37 nm Ge/perfect electric conductor structure for (e) TE and (f) TM polarization.