diffraction gratings and does - Breault Research Organization, Inc.

DIFFRACTION GRATINGS AND DOESSimulating Diffractive Optical Elements in ASAP. . . . .efficiencies. The next line that has only two numbers defines the next speculardirection with its associated triplets, and so on.What then are the additional a' b' f', a" b" b" terms, and so on? They are thediffraction angles and efficiencies corresponding to a diffraction envelope or,specifically, to the other orders of a diffraction grating. In one sense, a coating islike a diffraction grating operating only in the zeroth order (a, b, f), which isspecified by a single set of triplets. However, a diffraction grating can havemultiple sets of triplets simulating other diffraction order efficiencies. Thenumbers you enter are the discrete numbers of an envelope of the diffractionefficiency function at this wavelength and angle of incidence. The numbers cancorrespond directly to specific diffraction order efficiencies if you have only thisdata.The COATING MODELS/ USERBSDF technique is an appropriate way to modeldiffraction efficiencies. USERBSDF is a general scatter model and diffractiongratings produce discrete, deterministic scattering functions.Finally, multiple exposure holograms can be modeled by using the third form ofthe INTERFACE DIFFRACTive syntax. However, you specify only the zerothorder once. For example,ASAP Technical Guide 45