Polarization-Controlled Confined Tamm Plasmon Lasers

In this paper we report on the evidence of polarized and spatially localized emission of a Tamm laser. The polarized emission results from an anisotropic three-dimensional confinement of Tamm plasmon modes at the interface between an active semiconductor distributed Bragg reflector and a silver thin-film. The spatial confinement is achieved by patterning microrectangles with an aspect ratio of 2 in the top metallic layer. This geometrical birefringence is observed to split the fundamental confined Tamm mode into two modes, which result to be orthogonally polarized along the two sides of the structure. We measure a wavelength splitting between the nondegenerate modes of 0.2 nm, which turns out to be in good agreement with numerical calculations. This weak splitting, together with the strong wavelength dependence of the buried quantum wells gain curve, allows us to demonstrate the existence of a highly linearly polarized laser emission at 850 nm. By controlling the detuning between the confined Tamm modes and the gain curve, we report on a maximum degree of linear polarization in excess of 90%.