Plasmonic Airy Beam on Metal Surface

Optical Airy beam, as a novel non-diffracting and self-accelerating wave packet, has generated great enthusiasm since its first realization in 2007, owing to its unique physics and exciting applications. Here, we report a new form of this intriguing wave packet - plasmonic Airy beam, which is experimentally realized on a silver surface for the first time. By particular diffraction processes in a carefully designed nano-array structure, a novel planar Airy beam of surface plasmon polariton (SPP) is directly generated and a structural dependent phase tuning method is proposed to modulate the beam properties. This SPP Airy beam is regarded as a two-dimensional (2D) subwavelength counterpart of the 3D optical Airy beam in free space, allowing for on-chip photonic manipulations. Moreover, it possibly suggests a breakthrough in recognition of this unique wave packet in a polariton regime after its previous evolution from free particle to pure optical wave.