Numerical modelling of nonconformal gratings by the modified integral method

Grating designs of practical interest, with subtle features of efficiency curves sensitive to the data or requiring very accurate computations, are considered. Examples (conformal and non-conformal coated gratings, in both polarizations) include: grating with a very thin oxide layer; non-conformal grating having a very narrow resonance peak, sensitive to refractive index measurements and interpolation; non-conformal sinusoidal grating with coating in the form of semi-cylinders with turn points; echelle with a tapered coating. The results are obtained by two integral method codes of the PCGrateTM software. Implementation details and validation of results are discussed.

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