Amplification of SPPs in a methyl orange doped dielectric loaded SPPs waveguide

Abstract

Fabrication and characterization of straight dielectric loaded surface plasmon polaritons (DLSPP) waveguides doped with gain medium of methyl orange in their dielectric layer are investigated in this paper. The DLSPP waveguides are fabricated by using direct-laser writing. DLSPP waveguides with different widths and lengths are demonstrated. The DLSPP modes propagating in the waveguide is excited with a He-Ne laser at 632.8nm and pumped with a diode pumped solid state (DPSS) laser at a wave length of 532nm. A leakage radiation microscopy (LRM) is used to characterize the DLSPP modes. A propagation length without pump laser beam of 14.2um is obtained, corresponds to a propagation loss of 259cm -1 . We also get the optical gain as a function of the pumped irradiance. And an optical gain of 145cm -1 (a loss compensation of ~56%) is observed.