The invention relates to a laser device for emitting waves in a frequency range belonging to the terahertz range, characterized in that it includes the following, in combination: a wave guide (1) extending longitudinally along an axis A-A'; a superconducting coil (4) arranged coaxially to the wave guide (1) and arranged at a first end (112) of the wave guide (1); a p-Ge p-doped germanium crystal (3) arranged inside the coil (4) such that the turns of the superconducting coil (4) at least partially surround said p-Ge crystal (3); a cooling means (7) containing a coolant, the superconducting coil (4) and the p-Ge crystal (3) being arranged in the cooling means (7), and the wave guide (1) partially extending outside the cooling means (7); and a means (13) for removing the coolant from the wave guide