Observation of a spin degeneracy breaking in thermal radiation emitted from an inhomogeneous anisotropic lattice composed of coupled antennas supporting surface waves is presented. The spin degeneracy removal is manifested by a spin-dependent momentum splitting of the radiative mode which resembles the Rashba effect [1,2]. The spin split dispersion arises from the inversion asymmetry of the lattice. Our experiment confirms that the spatial rate of the inhomogeneity determines the degree of the spin dependent momentum redirection [3]. The influence of the inversion asymmetry on the dispersion was studied by comparing the results to those produced by homogeneous lattices and characterizing the behavior of the isolated thermal antennas [4].

References

[1] E. I. Rashba, Sov. Phys. Solid State 2, 1109 (1960).

[2] K. Ishizaka, M. S. Bahramy, H. Murakawa, M. Sakano, T. Shimojima, T. Sonobe, K. Koizumi, S. Shin, H. Miyahara, A. Kimura, K. Miyamoto, T. Okuda, H. Namatame, M. Taniguchi, R. Arita, N. Nagaosa, K. Kobayashi, Y. Murakami, R. Kumai, Y. Kaneko, Y. Onose, and Y. Tokura, Nat. Mater. 10, 521 (2011).

[3] N. Dahan, Y. Gorodetski, K. Frischwasser, V. Kleiner, and E. Hasman, Phys. Rev. Lett. 105, 136402 (2010).

[4] K. Frischwasser, I. Yulevich, V. Kleiner, and E. Hasman, Opt. Express 19, 23475 (2011).