V. Dhayalan et Jj. Stamnes, FOCUSING OF ELECTROMAGNETIC-WAVES INTO A DIELECTRIC SLAB - I - EXACT AND ASYMPTOTIC RESULTS, Pure and applied optics, 7(1), 1998, pp. 33-52
We present exact and asymptotic results for the electromagnetic field
inside a dielectric slab in terms of the given field or source current
outside the slab. Exact results for the reflected and transmitted fie
lds are also given. In particular, we provide explicit exact and asymp
totic results for the case in which the incident wave is a converging
electromagnetic wave generated by a time-harmonic aperture current. In
a separate paper our results are used to obtain exact and asymptotic
numerical results for the focused field inside the slab.