Plasmonic Airy beam manipulation by linear optical potentials

Abstract

Airy beams have attracted surging attention due to their non-diffracting and self-healing properties [1]. Those features have been employed for various applications, including optical trapping, plasma guiding and light bullets generation. Importantly, Airy beams have been recently introduced into the field of plasmonics [2] and present the only possible non-diffracting plasmon beams. Combined with the virtue of surface plasmons which could be confined down to the nanoscale, plasmonic Airy beams appear as promising candidates for subwavelength on-chip signal processing or particle manipulation. For such applications, the control of the acceleration of the Airy beam during propagation remains an intrinsic challenge due to (i) need to preserve the non-diffracting nature of the beam and (ii) need to control the propagation without changing the initial beam profile. Importantly, both of these conditions can only be satisfied when the Airy beams propagate in linear optical potentials of different strengths [3]. In this study, we suggest and demonstrate plasmonic Airy beam manipulations in a wedged metal-dielectric-metal (MDM) structure [Fig. 1(a)], where one of the metallic plates is tilted to produce an effective linear optical potential. We show both analytically and numerically that with different tilting angles, the plasmonic Airy beam deflection could be enhanced, compensated or even reversed, meanwhile still maintaining the self-healing properties.