Shedding light on evolution of Raman line shape with probing laser power: Light-induced perturbation in electron-phonon coupling

The laser power mediated changes in the Raman line shape have been considered in terms of interference between discrete phonon states |rho > and the electronic continuum states |kappa > contributed by Urbach tail states. The laser-induced effects are treated in terms of the increase in the surface temperature and thereby the scaling of electronic disorder, i.e., Urbach energy, which can further contribute to the electron-phonon interactions. Therefore, the visualization of this effect is attempted analytically as a perturbation term in the Hamiltonian, which clearly accounts for the observed changes with laser power. This has been investigated based on the experimental results of laser power dependent Raman spectra of bulk EuFeO3 and silicon nanowires, which are found to provide convincing interpretations.