Characterizing the non-paraxial Talbot effect of two-dimensional periodic arrays of plasmonic gold nanodisks by differential interference contrast microscopy†
Exploiting the working principle of conventional differential interference contrast (DIC) microscopy, we experimentally investigate the non-paraxial Talbot effect of two-dimensional periodic arrays of gold nanodisks (AuNDs) with a periodicity ao comparable to the excitation wavelength λ. In the non-paraxial regime, strongly contrasting self-image patterns at the Talbot and fractional Talbot distances appeared perpendicularly to the AuND array. The experimental self-image distances were comparable to the calculated non-paraxial Talbot distances at two excitation wavelengths (540 nm and 600 nm). Beyond the paraxial limit, Talbot distances were observed at positions smaller than the paraxial Talbot distance.