三、单缝衍射 设缝宽为a A 2 A(X)= 0 X 2 2 kax ik ikax kax dr- e 2f aA kx e kax 2f kax ,πasin O B 2f 几三、单缝衍射 ⎪ ⎪ ⎩ ⎪ ⎪ ⎨ ⎧ −<> <<− = 2 , 2 0 22 )( a X a X a X a A XA f kax f kax aA ikx Af XAx f ikax f a ikax a xX f ik 2 2 sin eede)( 2 2 2 2 =⎟ ⎟ ⎠ ⎞ ⎜ ⎜ ⎝ ⎛ = −= − −∫ ψ 2 0 sin ⎟ ⎟ ⎠ ⎞ ⎜ ⎜ ⎝ ⎛ =∴ β β II X x f 0 s θ 设缝宽为 a λ θ β π sin 2 a f kax ==