Critical coupling to Tamm plasmons

The conditions of critical coupling of light to Tamm plasmons are investigated with comprehensive numerical simulations, highlighting the parameters that maximise absorption of incident light in the metal layer. The asymmetric response in reflection and absorption with respect to the direction of incidence is discussed, the two cases yielding different optimal coupling conditions. These findings are relevant for the design of optimised Tamm structures, particularly in applications such as narrow-band thermal emitters, field-enhanced spectroscopy and refractive-index sensing.