Field intensification. Example 2.

• Constitutive parameters: ε = -0.2 + 0.001i and μ = -1.3 + 0.001i. λ/d=1.7, a coupling between the incident EPW and an ESW is expected to fall in regions corresponding to low reflectivity (θ < θ_c=30.66 degree).

	Efficiency |R0(θ)|2 corresponding to the specularly reflected order    and for different values of h/d in the range 0.005–0.030.
	Map of |R0(θ)|2 as a function of θ and h/d. When h/d is increased from 0.03   (maximum value in the above figure), the maximum value of the reflectivity    reaches a increasingly larger value. The introduction of a weak    corrugation in an poorly reflecting surface, produces high reflectivities in    angular regions corresponding to ESW excitation. For example, when h/d=0.06,    the surface reflects 85 % of the incident power.
	Map |R-1(θ)| as a function of θ and h/d. Contrary to the behavior found in the    previously described regimes (After total reflection ), we observed that the amplitude    of the evanescent order,which is phase matched with the ESW, does not take its    maximum value under the same conditions where maximal absorption of the incident    wave occurs, a feature that should prevent us from obtaining maps of the ESW    dispersion relation by optically detecting the angular position of the minima, as is of    common use in conventional prism and grating couplers.

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