  Hybridization of surface-plasmon and dielectric waveguide whispering-gallery
modes are demonstrated in a semiconductor microdisk laser cavity of
sub-wavelength proportions. A metal layer is deposited on top of the
semiconductor microdisk, the radius of which is systematically varied to enable
mode hybridization between surface-plasmon and dielectric modes. The
anti-crossing behavior of the two cavity mode types is experimentally observed
via photoluminescence spectroscopy and optically pumped lasing action at a
wavelength of 1.3 micron is achieved at room temperature.
