x + ( 2π ax ) 2 , but a linear dispersion for the TE mode ω k,TE = c n eff ( 2π ax ± k x ), where a x is the lattice constant in the x-direction for the plasmonic lattice and n eff is the effective index of refraction of the ambient material in the cavity. Due to this polarization dependence for the cavity dispersion with plasmonic cavities, both polarizations must be considered for such systems. However, for this section, we will focus on Fabry-Pérot cavities. We refer the reader to Ref. 135 for further discussions on plasmonic cavities.