作者kevin60405 (廷廷)
看板Physics
標題[問題] 雙狹縫繞射問題
時間Wed Oct 7 23:53:53 2009
這是Haliday普物中的敘述
In the double-slit experiment of Chapter 35, we implicitly assumed thar the
the slit were much narrower than the wavelength of the light illuminating them;
that is, a<<λ. For such narrow slits the central maximum of the diffraction
pattern of either slit covers the viewing screen.Moreover, the interference of
light from the two slits produces bright frines with appoximately the same
intensity.
文中說到當入射波長遠大於狹縫寬度 還是會有干涉條紋
而且此時強度不隨空間分佈
可是我以前學的是 當入射波長大於狹縫寬度時 會呈現消散波的形式
波行進不到幾個波長就沒了 更不要說波長"遠大於"狹縫寬了
那haliday作者的解釋是怎麼一回事....
--
※ 發信站: 批踢踢實業坊(ptt.cc)
◆ From: 125.225.19.123
※ 編輯: kevin60405 來自: 125.225.19.123 (10/07 23:54)
1F：→ leo80042:會不會是你把"狹縫寬度"和"狹縫間距"搞混了? 10/08 00:48
2F：→ leo80042:高中學的雙狹縫干涉是假設狹縫寬度很小，沒有單狹縫繞射 10/08 00:49
3F：→ leo80042:效應。但若把狹縫寬度也考慮進來，看到的條紋是干涉和繞 10/08 00:49
4F：→ leo80042:涉結合在一起。(好久沒念了，有錯請指正謝謝^^") 10/08 00:50
5F：→ grind:你實在很行....消逝場馬上又變成你以前學的... 10/08 00:56
6F：→ grind:first of all, the scale of evanescent wave and that of 10/08 00:57
7F：→ grind:diffraction are much different, about several orders.... 10/08 00:58
8F：→ grind:the auther just talked about the "viewing screen". 10/08 00:58
9F：→ grind:the slit width, a, is about one-tenth and the viewing 10/08 00:59
10F：→ grind:screen will be smaller than the central bright zone. 10/08 01:00
11F：→ grind:so that we don't take diffraction in consideration, when 10/08 01:01
12F：→ grind:we are having a experiment of double-slit interferrence 10/08 01:02
13F：→ grind:with a quite small slit width. 10/08 01:03
14F：→ kevin60405:不太懂 所以就算波長>>狹縫寬 還是有干涉條紋? 10/08 17:14