  Nonlinear optical behavior of recently introduced surface plasmon toy black
hole models has been considered. Physical realization of these models involves
droplets of liquid on a metal surface, which supports propagation of surface
plasmons. Such droplets are shown to exhibit strongly enhanced nonlinear
optical behavior in the frequency range near the surface plasmon resonance of a
metal-liquid interface. This enhancement may be responsible for the missing
orders of magnitude of field enhancement in the surface enhanced Raman
scattering effect. In addition, experimental observation of the recently
predicted optical second harmonic generation near the toy event horizon is
reported. Finally, the possibility of toy Hawking radiation observation is
discussed, and the expression for the effective Hawking temperature of a toy
surface plasmon black hole is derived. The effective Hawking temperature
appears to be in the range of a few hundreds Kelvin for the realistic droplet
shapes, which may lead to a surprising conclusion that the shapes of the liquid
droplets on metal substrates are to some degree determined by the Hawking
radiation.
