Binary quasi-periodic hole array with the completely suppression of high order diffractions

Spectral measurement plays a central role in nearly allaspects of modern optical science and engineering. In a wide spectral measurement, the unwanted higher order diffraction overlaps the first one, which greatly degrades precision of analysis. And the sinusoidal transmission gratings with only 0-order and +1/-1 order diffractions are more difficult to fabricate than the black-white structure. Therefore, it has been a goal to design the black-white structures with the suppression of high order diffractions. Recently, various binary structures with suppression of high order diffractions have been developed. However, the reported works can't obtain complete suppression of high order diffractions since it's difficult to realize the complex shapes or the very small gaps between the two adjacent grooves. Moreover, these structures based on the one dimensional grating can't freely stand. Unfortunately, the supporting membrane will absorb 80% energy of the X-ray. Here we propose a free standing quasi-periodic hole array with the completely suppression of high order diffractions. The hole distribution according to some statistical law results in a desired diffraction pattern. The structure is scalable from X-ray to far infrared wavelengths.We start the design from the triangle array of rectangular holes and the holes are shifted by s along the ξ axis according to the probability distribution ρ(s) = (π/Pξ) · cos(2πs/P<;sub>ξ<;/sub>),IsI <; P_ξ/4.