We examine experimentally the excitation of plasmon resonances in ordered two-dimensional diffractive arrays of gold nanoparticles placed in asymmetric refractive index environment. The excitation of the plasmon modes with narrow spectral profile in asymmetric environment was experimentally verified. The ability to tune the wavelength of these resonances in the near infrared range by varying the structural parameters of the periodic arrays in combination with size and geometry of the constituent nanoparticles is discussed.
