Coupled nanowire-based hybrid plasmonic nanocavities on thin substrates

Abstract

We theoretically analyze nanowire-based hybrid plasmonic nanocavities on thin substrates at visible wavelengths. In the presence of thin suspended substrates, the hybrid plasmonic modes, formed by the coupling between a metal nanowire and a dielectric nanowire with optical gain, exhibit negligible substrate-mediated characteristics and overlap better with the gain region. Consequently, the confinement factor of the guided hybrid modes is enhanced by more than 42%. However, the presence of significant mirror loss remains the main challenge to lasing. By adding silver coatings with a sufficient thickness range on the two end facets, we show that the reflectivity is substantially enhanced to above 50%. For a coating thickness of 50 nm and cavity length of about 4 μm, the quality factor is above 100.

Channel Plasmon Nanowire Lasers with V-Groove Cavities

“…With the advantage of hybrid plasmonic modes, electric field can be localized in dimensions beyond the diffraction limit with low-loss propagation [ 25 , 26 ]. So, our investigation focuses on the guiding and lasing properties in subwavelength diameter dimension, 40 to 220 nm.…”