title: Plasmonic gap-mode nanocavities with metallic mirrors in high-index cladding.
abstract: We theoretically analyze plasmonic gap-mode nanocavities covered by a thick cladding layer at telecommunication wavelengths. In the presence of high-index cladding materials such as semiconductors, the first-order hybrid gap mode becomes more promising for lasing than the fundamental one. Still, the significant mirror loss remains the main challenge to lasing. Using silver coatings within a decent thickness range at two end facets, we show that the reflectivity is substantially enhanced above 95 %. At a coating thickness of 50 nm and cavity length of 1.51 μm, the quality factor is about 150, and the threshold gain is lower than 1500 cm(-1).
authors.affiliation: Department of Photonics, National Chiao Tung University, Hsinchu 30010, Taiwan.
authors.forename: Pi-Ju
authors.initials: PJ
authors.lastname: Cheng
authors.forename: Chen-Ya
authors.initials: CY
authors.lastname: Weng
authors.forename: Shu-Wei
authors.initials: SW
authors.lastname: Chang
authors.forename: Tzy-Rong
authors.initials: TR
authors.lastname: Lin
authors.forename: Chung-Hao
authors.initials: CH
authors.lastname: Tien