  Spectrally-tailored interactions of light with material interfaces offer many
exciting applications in sensing, photo-detection, and optical energy
conversion. In particular, complete suppression of light reflectance at select
frequencies accompanied by sharp phase variations in the reflected signal forms
the basis for the development of ultra-sensitive singular-phase optical
detection schemes such as Brewster and surface plasmon interferometry. However,
both the Brewster effect and surface-plasmon-mediated absorption on planar
interfaces are limited to one polarization of the incident light and oblique
excitation angles, and may have limited bandwidth dictated by the material
dielectric index and plasma frequency. To alleviate these limitations, we
design narrow-band super-absorbers composed of plasmonic materials embedded
into dielectric photonic nanostructures with topologically-protected
interfacial Tamm plasmon states. These structures have planar geometry and do
not require nanopatterning to achieve perfect absorption of both polarizations
of the incident light in a wide range of incident angles, including the normal
incidence. Their absorption lines are tunable across a very broad spectral
range via engineering of the photon bandstructure of the dielectric photonic
nanostructures to achieve reversal of the geometrical phase across the
interface with the plasmonic absorber. We outline the design strategy to
achieve perfect absorptance in Tamm structures with dissipative losses via
conjugate impedance matching. We further demonstrate via modeling how these
structures can be engineered to support sharp asymmetric amplitude resonances,
which can be used to improve the sensitivity of optical sensors in the
amplitude-only detection scheme that does not require use of bulky and
expensive ellipsometry equipment.
