Case1: Let z = 0 plane represent the interface between two media. Medium 1 is characterised by and medium 2 is characterized by .

Let the subscripts 'i' denotes incident, 'r' denotes reflected and 't' denotes transmitted field components respectively.

The incident wave is assumed to be a plane wave polarized along x and travelling in medium 1 along direction. From equation (6.24) we can write

..................(6.49.a)

......................(6.49.b)

where and .