diffraction gratings and does - Breault Research Organization, Inc.

DIFFRACTION GRATINGS AND DOESFundamentals of Diffractive Optical Elements. . . . .The width of the masks for each step is a function of the type of phase surface. Forthe blazed grating, the width of the mask on the first etch is half of the modulo 2phase interval. The width in subsequent mask intervals is half that of the previousmask. For a circularly symmetric case, like the thin lens, the width of the mask onthe first etch, step, or transition begins at the radial value corresponding to amodulo phase depth. Subsequent radial transition points occur at multiples of themodulo phase depth. On the second mask, the transitions occur at integermultiple modulo /2 phase depths, and so on.The entire binary optics process as well as required transition points and etchdepths are discussed in great detail in Swanson’s report from the MassachusettsInstitute of Technology (MIT) titled “Binary Optics Technology: The Theory andDesign of Multi-level Diffractive Optical Elements”. The transition points andetch depths are shown in Equation 15 and Equation 15.TRANSITION POINTSEquation 15(EQ 15)ASAP Technical Guide 27