  We experimentally studied the dynamics of optically excited hotspots in
current carrying WSi superconducting nanowires as a function of bias current,
bath temperature and excitation wavelength. We discovered that: (1) the hotspot
relaxation is a factor of ~ 4 slower in WSi than in NbN; (2) the hotspot
relaxation time depends on bias current, and (3) the current dependence of the
hotspot relaxation time changes with temperature and wavelength. We explained
all of these effects with a model based on quasi particle recombination.
