Abstract

The diffraction of electromagnetic waves from a periodic structure has been intensively investigated both in classical and conical (off-plane) diffraction mountings.¹⁻³ In this paper, we present the multiple diffraction rings of a two-dimensional planar phase grating (so-called Dammann grating⁴) for the conical diffraction mounting and propose a simple method for measuring the unknown period of the grating as a possible application. Consider a unit amplitude plane wave incident on a two-dimensional (cross) surface-relief grating at a spherical angle (θ₁,ϕ₁), as illustrated in Fig. 1: where the components of the incident wave vector k₁ are (α_o, — ß_o, —γ_oo) = k_on₁ (sinθ,cosϕ₁, —sinθ₁,sinϕ₁, —cosθ₁, k_o is the wave vector in vacuum, and ni is the refractive index of regions 1 and 3.

© 1994 IEEE