304 Ultrashort Sources I: Fundamentals
is recovered, which takes a time of the order of the gain material lifetime (typi-
cally microseconds). The output of such a laser consists in bursts of Q-switched
mode-locked pulse trains.
This first subsection is dedicated to straightforward linear cavities. The case
of ring cavities and some linear cavities with two pulses per cavity round-trip is
more complex because it involves mutual coupling between counter propagating
pulses in an absorber or nonlinear loss element.
5.3.1. Rate Equations for the Evolution of the
Pulse Energy
Nonlinear Element
The hypothetical laser to be considered here consists of a gain and a loss
medium whose parameters vary with the intensity and the energy of the evolving
pulse, depending ...