Two-dimensional Bessel-like surface plasmon-polariton beams

We present experimental evidence of non-diffracting two-dimensional Bessel-like surface plasmon-polariton (SPP) beams using the simultaneous excitation of two grating couplers forming an angle. The Bessel-like SPP beam properties were verified experimentally using the plasmon-coupled leakage radiation microscopy technique. The good agreement between simulations and measured intensity beam profiles confirms the effectiveness of the grating-coupler approach. Our results revealed that the spreading and propagation length characteristics of the Bessel-like SPP beams are primarily influenced by the angle between the grating couplers.