Agenda today 1.Single slit diffraction 2.Diffraction by a circular aperture 3.Optical grating 4.X-ray diffraction32
Agenda today 1. Single slit diffraction 2. Diffraction by a circular aperture 3. Optical grating 4. X-ray diffraction32
Diffraction Fresnel diffraction:ifa source s and the viewing screen are each a finite distance from an intermediate object,the resulting diffraction pattern is called fresnel diffraction(菲涅尔衍射)
Diffraction Fresnel diffraction:if a source s and the viewing screen are each a finite distance from an intermediate object, the resulting diffraction pattern is called fresnel diffraction(菲涅尔衍射)。 P
Fraunhofer diffraction:if both the source and the screen are far from the intermediate object,the diffraction is called fraunhofer diffraction(夫朗和 费衍射)。 D
Fraunhofer diffraction:if both the source and the screen are far from the intermediate object, the diffraction is called fraunhofer diffraction(夫朗和 费衍射)。 P
For constructive asin0=±(2k+1) interference For destructive asin0=±kλ minima interference 2 0 -2
For constructive interference : sin (2 1) 2 a k a k sin minima01-2-12 For destructive interference
2 0 -2 asin0=±k入 the angular width of<asin< central maxima: Φ=20≈2sin0= 22 a
0 1 -2 -1 2 the angular width of central maxima: a k sin asin 2 2 2sin a