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In this paper, a novel hybrid plasmonic waveguide with a metal ridge and an MgF2 dielectric layer is demonstrated at ultraviolet band. We investigate the propagation distance, the scaling factor and the figure of merit by using the finite element method. The structure enables low scaling factor and long propagation distance. Compared to the previous structure with a metal plate, this waveguide has better performance. And the structure can be used as a nanolaser and has broad application prospects in optoelectronic integrated circuits, biological detection and so on.

In recent years, surface plasmons are introduced to break diffraction limit of waveguide, whose size must be larger than the half wavelength of the optical field in all three dimensions [

The geometry of the proposed waveguide is shown in

low-index MgF_{2} dielectric layer, a SiO_{2} layer and a high-index GaN nanowire. The width of the metal layer is 300 nm, and its height is 100 nm. The length of the GaN nanowire L is 30 μm, its radius is r. The radius of the metal ridge is fixed at 35 nm. The thickness of the MgF_{2} dielectric layer is 5 nm. At the working wavelength of 370 nm, the refractive indices of Al, MgF_{2}, SiO_{2} and GaN are 0.38829 + 4.3466i, 1.3856, 1.46 and 2.65, respectively [

_{2} dielectric layer into the design, the electric field energy is concentrated in a tiny area.

To quantify the mode properties, we introduce the indices of the mode scaling factor (

Here, the effective mode area

In the above expressions, E is the electric field intensity of the hybrid mode and

where

The

The lager _{2} dielectric layer.

The pump threshold is the minimal value the gain reaches when achieving lasing action. It is related to the nanowire length L and the end facet reflectivity R. The R [

The lasing threshold is calculate^{ }[

where

We present a new type of ultraviolet waveguide based on surface plasmons which attains deep-subwavelength scale and has long propagation distance. By using the COMSOL Multiplicity software, we investigate the light field distribution, and analyze the effect of the radius of the gain medium nanowire on the properties and the lasing threshold. The results show that the larger nanowire radius causes the better performance of the proposed waveguide. So we can select the optimal radius of the nanowire as 80 nm. In this case, the SF, the D and the threshold are 0.0359,

We acknowledge support from the Hundred-Talent Program of Hebei Province and the Natural Science Foundation of Hebei Province in China.

Zhiquan Li,Yajuan Wang,Jiahuan He,Dandan Feng,Erdan Gu,Wenchao Li, (2016) An Ultraviolet Hybrid Plasmonic Waveguide for Nanolaser Applications. Optics and Photonics Journal,06,19-23. doi: 10.4236/opj.2016.68B004