What happens if the angle < Brewster's angle?

[garylau]

Sorry
i have question for TM polarization.
i don't understand why if the angle < brewster's angle,then the reflected light will experience an pi phase shift?
can anybody explain why?

 

[blue_leaf77]

Take a look at these equations, especially $r_p$ which is the (complex) reflection coefficient for TM polarization. In particular, you will be interested in the so-called internal reflection, that is when $n_2 < n_1$.