  Transient state of femtosecond laser excited bismuth has been studied by
various groups with time-resolved optical, x-ray, and electron probes at the
deposited energy density from below through up to several times the equilibrium
enthalpy of melting. However, the interpretations of the experimental results
are controversial: the optical probes reveal the absence of transition to the
melting phase while the authors of x-ray and electron diffraction experiments
claim the observation of ultrafast non-thermal melting. The presented analysis,
based on temperature dependence of bismuth optical properties, unequivocally
shows a purely thermal nature of all the observed fs-laser induced
transformations in bismuth.
