Entropy bounds in nonlinear quantum nanooptics
  Optical entropy bounds for metal nanoparticles immersed in nonlinear optical media and for nonlinear dielectric microdroplets on metal surfaces are calculated near the frequency of the surface plasmon resonance. Similar to the Bekenstein-Hawking result for the black hole entropy, the entropy bounds in nonlinear quantum nanooptics may be expressed as the ratios of the droplet perimeter (nanoparticle area) to the effective Planck length (effective Planck length squared). 
Igor I. Smolyaninov