  While the thermoelectric and photoconduction effects are crucial in pristine
and low-doped graphene, the bolometric effect is known to dominate the
photoresponse in biased graphene. Here, we present a detailed microscopic
investigation of the photoresponse due to the bolometric effect in graphene.
Based on the semiconductor Bloch equations, we investigate the time- and
momentumresolved carrier dynamics in graphene in the presence of a constant
electric field under optical excitation. The magnitude of the bolometric effect
is determined by the optically induced increase of temperature times the
conductivity change. Investigating both factors independently, we reveal that
the importance of the bolometric effect in the high-doping regime can be mostly
ascribed to the latter showing a parabolic dependence on the doping.
