
94 Femtosecond Optics
2.5. ELEMENTS WITH ANGULAR DISPERSION
2.5.1. Introduction
Besides focusing elements there are various other optical components which
modify the temporal characteristics of ultrashort light pulses through a change
of their spatial propagation characteristics.
Even a simple prism can provide food for thought in fs experiments. Let us
consider an expanded parallel beam of short light pulses incident on a prism,
and diffracted by the angle β = β(), as sketched in Figure 2.17. As discussed
in Chapter 1, a Gaussian beam with beam waist w
0
self-diffracts by an angle
of approximately θ = λ/πw
0
. In the case of a short pulse (or white light), ...