Fig. 3.
Hyperbolicity and two photon emitters in multiple bands. Two-polariton spectral enhancement defined as in Eq. 6 for a spherical emitter as a function of transition frequency [1,600 (Left), 2,300 (Center), and 3,000 (Right) cm−1], plotted on log10 scale. The spectral enhancement is plotted with respect to emission frequency and atom-surface separation between 5 and 10 nm. Hyperbolicity allows for enhancement over a large range of frequencies compared with isotropic systems. Moreover, distance can be used to tune the width of the spectrum.