A mirror with a larger effective critical angle can be made by exploiting diffraction (with non-zero losses) that occurs from stacked multilayers. The critical angle of total reflection, in degrees, becomes approximately , where  is the "m-value" relative to natural nickel.
To produce a larger effective critical angle, a mirror can be crafted by exploiting diffraction effects from layered structures, which result in some energy loss. This leads to an approximate value for the critical angle of total reflection, expressed as , where  is the "m-value" relative to natural nickel.