  The behavior of a dynamical system can exhibit abrupt changes when it crosses
a tipping point. To prevent catastrophic events, it is useful to analyze
indicators of the incoming bifurcation, as the divergence of the relaxation
time of the system when approaching the critical point. However, this
phenomenon, called critical slowing down (CSD), is hardly measurable in real
physical systems. In this paper we provide experimental evidence of CSD in a
laser system crossing the emission threshold and we analyze how it is affected
by a time changing parameter and by noise.
