Taking magnetostatic surface wave diffraction as an example, this paper theoretically investigates the 2D diffraction pattern arising in the far-field region of a ferrite slab in the case of a plane wave with noncollinear group and phase velocities incident on a wide, arbitrarily oriented slit in an opaque screen. A universal analytical formula for the angular width of a diffracted beam is derived, which is valid for magnetostatic and other types of waves in anisotropic media and structures (including metamaterials) in 2D geometries. It is shown that the angular width of a diffracted beam in an anisotropic medium can not only take values greater or less than $\lambda_0/D$ (where $\lambda_0$ is the incident wavelength, and $D$ is the slit width), but can also be zero under certain conditions.

PACS: 41.20.Gz, 41.20.Jb, 42.25.Fx, 75.70.−i (all) DOI: 10.3367/UFNe.0182.201212e.1327 URL: https://ufn.ru/en/articles/2012/12/e/ 000315989900005 2-s2.0-84875174749 2012PhyU...55.1239L Citation: Lock E H "Angular beam width of a slit-diffracted wave with noncollinear group and phase velocities" Phys. Usp. 55 1239–1254 (2012) BibTexBibNote ® (generic)BibNote ® (RIS)MedlineRefWorks Received: 4th, April 2011, revised: 5th, September 2011, accepted: 4th, October 2011 Оригинал: Локк Э Г «Угловая ширина луча при дифракции на щели волны с неколлинеарными групповой и фазовой скоростями» УФН 182 1327–1343 (2012); DOI: 10.3367/UFNr.0182.201212e.1327