Huygens's Principle:海更士定理

Every point on a primary wavefront serves as the source of spherical secondary wavelets , such that the primary wavefront at some later time is the envelope of these wavelets.   Moreover,the wavelets advance with a speed and frequency equal to those of the primary wave at each point in space.

每個波前面的任一點均可視為新的點波源,各自發出球面波向外傳遞,而新的波前即為這些球面波的包絡面.甚且,新的球面波之速度與頻率與原波相同.

灰色圓圈即為包絡面,注意新的波源產生在舊波的波前上,而向外擴散.下面即為一個圓形波.

作者:莊文吉   Wen-Jye Chuang    若有任何問題或建議,敬請不吝賜教