Abstract
Using terahertz magneto-spectroscopy we aim to determine the vortex mass and its dependence on temperature and hole doping in cuprate films and to understand the role of disorder in ultrathin superconducting film in the vicinity of the superconductor-insulator transition and how it affects their physical properties. Our laboratory facility offers a unique combination of time-domain and frequency-domain laser THz spectroscopy. The former furnishes us with frequency-dependent conductivity over a wide frequency range, and the latter allows us to form circularly polarized beams. The dependency on the helicity indicates the mass of the vortex.