Enhanced nonlinear frequency conversion and Purcell enhancement at exceptional points

Exceptional points (EPs) were recently predicted to modify the spontaneous emission rate or Purcell factor of narrow-band emitters embedded in resonant cavities. We demonstrate that EPs can have an even greater impact on nonlinear optical processes like frequency conversion by deriving a general formula quantifying radiative emission from a subwavelength emitter in the vicinity of a triply resonant {\ensuremath{\chi}}^{(2)}cavity that...