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Title: | 光波於介質中波速改變之機制與探討 The mechanism for the reduced speed of light in medium |
Authors: | Chia-Kuei Jen 任家逵 |
Advisor: | 陳義裕(Yih-Yuh Chen) |
Keyword: | 電磁學,折射,散射,司乃爾定律,波動方程式,微擾理論,格林函數, Electromagnetic theory,refraction,scattering,wave equations,perturbation theory, |
Publication Year : | 2017 |
Degree: | 碩士 |
Abstract: | 一般在探討光波之折射現象時,我們習慣從馬克士威方程式出發。並假設在沒有自由電子之下,分別寫出真空與介電質之下的電磁波的波動方程式並比較兩者的波速以及材料間的介電常數與磁導率,得出光波的波速在介電質中的變化量恰巧為折射率。然而,依上述推導的方式,我們很難看出光波的波速在介電質中變化的機制。在此篇論文中,我們會更進一步將介電質的影響當作一個微擾量,將其視為真空波動方程式的來源項並探討正向入射以及斜向入射的情況。我們先對該方程式作正規微擾理論並修正波在無窮遠距離下發散之情形。之後,我們提出波速改變的物理原因來自入射波與介電質材料之間的散射。接者,我們以格林函數的方式來迭代該微擾方程式以驗證此物理想法。最後,我們以修正波數以及空間尺度的方式,來得到相同的結論。 The change in the wave speed of light incident upon a simple medium can be simply derived using Maxwell's equations, which gives a nice and simple explanation of the index of refraction. However, this change in the wave speed is only apparent, as it is the combined effect of all the EM waves generated by the atoms when they interact with the incident light. Indeed, all these waves actually propagate at c, the speed of EM waves at vacuum. We use various approaches to illustrate this idea and give a simple account of why a wave changes its direction of propagation when it enters obliquely in a medium. |
URI: | http://tdr.lib.ntu.edu.tw/jspui/handle/123456789/70067 |
DOI: | 10.6342/NTU201800339 |
Fulltext Rights: | 有償授權 |
Appears in Collections: | 物理學系 |
Files in This Item:
File | Size | Format | |
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ntu-106-1.pdf Restricted Access | 1.51 MB | Adobe PDF |
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