Laser-I

Module 7 : Laser- I

Lecture : Line Broadening in Lasers

$\includegraphics{doppler.eps}$

	1. The time period in the observer's frame is dialated. If $\tau_0=1/\nu_0$ is the period of emission, the period as seen in the
	observer's frame is $\tau = \tau_0/\sqrt{1-v^2/c^2}$ .
	2. As the source moves towards the observer, the separation between the successive crests appears as
	$\displaystyle \lambda = c\tau-v\tau = \frac{(c-v)}{\sqrt{1-v^2/c^2}}$