All-dielectric nanolaser
  We demonstrate theoretically that a subwavelength spherical dielectric nanoparticle coated with a gain shell forms a nanolaser. Lasing modes of such a nanolaser are associated with the Mie resonances of the nanoparticle. We establish a general condition for the lasing threshold and show that the use of high refractive index dielectric media allows for lasing with a threshold significantly lower than that for nanolasers incorporating lossy plasmonic metals. 
D. G. Baranov, A. P. Vinogradov, and A. A. Lisyansky
cond-mat.mes-hall physics.optics