Enhanced A1g Raman response in unconventional superconductors due to Higgs oscillations

The Higgs in superconductors is a collective amplitude mode which can couple to light only in a non-linear Raman-like process. Despite being so far elusive in most experiments because of physical and technical reasons, in d-wave superconductors the excitation of the Higgs mode can become detectable in polarization dependent experiments. In our work, we have calculated the Raman contribution of the amplitude mode from a new perspective, including many-body dressing effects, demonstrating its role in the long-standing problem concerning the intensity of the A1g Raman spectrum in cuprates. Moreover, we apply our scheme to predict the presence of measurable characteristic oscillations in THz quench-optical probe time-dependent reflectivity experiments.