We study light diffraction in the periodically modulated ultrathin metal films both analytically and numerically. Without modulation these films are almost transparent. The periodicity results in the anomalous effects, such as suppression of the tran
smittance accompanied by a strong enhancement of the absorptivity and specular reflectivity, due to excitation of the surface plasmon polaritons. These phenomena are opposite to the widely known enhanced transparency of periodically modulated optically thick metal films. Our theoretical analysis can be a starting point for the experimental investigation of these intriguing phenomena.
