Weak-field nonlinear dynamic conductivity in a quantum well with a transverse magnetic field

It is shown that the dynamic differential conductivity in a quantum-well heterostructure permeated by a static magnetic field orthogonal to its plane should decrease significantly for alternating electric-field amplitudes much lower that those in a conventional semiconductor. This effect can be used, e.g., to create a low-threshold saturable absorber for electromagnetic radiation with a frequency of tens of gigahertz.