Physical Electronics Dept.

You are invited to attend a lecture

By

Dr. Gorodetski Yuri

ISIS, Université de Strasbourg, 8 allée Gaspard Monge, 67000 Strasbourg, France

Twisted plasmons and chiral light

Surface plasmons (SP) – collective oscillations of conduction electrons in the vicinity of metallic surface – have been intensively studied since the pioneer work of Ritchie¹. Recently, owing to a new ability of subwavelength surface structuring and nano-scale characterization, the unique properties of SPs have been recognized². Surface-confinement of the plasmons and their resonant behaviour enable a high energy concentration in the near-field subwavelength volumes. Accordingly, SPs were explored for their potential in miniaturizing of optical devices³. Also, the confinement leads to a high sensitivity of SPs with respect to refractive index changes which is exploited in bio-detection schemes and characterization strategies. Nevertheless, some fundamental physical properties of these surface waves remain controversial and counter-intuitive. In this talk, we will discuss some peculiar phenomena occurring in light-SP coupling process. We will show that a chiral light impinging on specifically designed surface structures leads to an interesting dynamics of the excited plasmonic field^4-6. This field, in turn, may be rather detected in the near-field, providing a means for ultra-sensitive chirality measurement of light⁴, or can be reemitted to the far-field, giving rise to singular beams carrying orbital angular momentum⁵. Finally we will discuss the potential of these structures for polarization management and beam shaping, as well as stress the fundamental importance of these phenomena⁶.

References

[1]          R. H, Ritchie, Phys. Rev. 106, 874 (1957).

[2]          T. W. Ebbesen, H. J. Lezec, H. F. Ghaemi, T. Thio, and P. A. Wolff, Nature, 391, 667 (1998).

[3]          C. Genet and T. W. Ebbesen, Nature, 455, 39 (2007).

[4]          Y. Gorodetski, K. Y. Bliokh, B. Stein, C. Genet, N. Shitrit, V. Kleiner, E. Hasman, and T. W. Ebbesen, Phys. Rev. Lett. 109, 013901 (2012).

[5]          Y. Gorodetski, C. Genet, and T. W. Ebbesen, “Generating far-field orbital angular momentum from near filed optical chirality”, submitted to Phys. Rev. Lett. (2012).

[6]          Y. Gorodetski, E. Lombard, A. Drezet, C. Genet, and T. W. Ebbesen, Appl. Phys. Lett. 101, 201103 (2012).