Asymmetric beam deflection by doubly grooved binary gratings.

It is demonstrated theoretically and experimentally that the inversion symmetry of the diffraction pattern of a binary grating at normal incidence can be efficiently broken by the use of nonsymmetric profiles with wavelength-scale transverse features. Theoretically, binary gratings with two grooves (of unequal widths but with the same depth) within the period can deflect as much as ∼80% of normally incident radiation into the minus first diffraction order when the deflection angle is 45°.