The problem of diffraction of a plane wave from a half-infinite infinitely thin perfectly conducting screen is one of the few in optics that can be solved exactly, as was first done by Sommerfeld (1896; Born and Wolf 1999, p. 370).
References
Born, M. and Wolf, E. "Two-Dimensional Diffraction of a Plane Wave by a Half-Plane." §11.5 in Principles of Optics: Electromagnetic Theory of Propagation, Interference, and Diffraction of Light, 7th ed. Cambridge, England: Cambridge University Press, pp. 565-578, 1999.
Sommerfeld, A. Math. Ann. 47, 317, 1896.
