Application of point diffraction interferometry for middle spatial frequency roughness detection Svechnikov, M. V. ; Chkhalo, N. I. ; Toropov, M. N. ; Salashchenko, N. N. ; Zorina, M. V. Abstract Publication: Optics Letters Pub Date: January 2015 DOI: 10.1364/OL.40.000159 Bibcode: 2015OptL...40..159S