Transmission characteristic in random medium thin film

By means of transfer matrices, the transmission spectral of random medium thin film is calculated, which consists of two-type medium. It is found that the thin film has selective transmission effect to the light within ultraviolet region, and that the larger the strength of randomness, dielectric constant and thickness of random layer (are), the narrower the half-width of transmission light becomes. Otherwise, no matter how the other parameters change, the light, whose wavelength is equal to the thickness of first layer, can transmit the thin film when the dielectric constant of first layer is one.