Intraband absorption in semiconductor quantum wells in the presence of a perpendicular magnetic field

The intraband light absorption between conduction-band states in symmetric semiconductor quantum wells in the presence of a perpendicular magnetic field is discussed. By theoretical analysis three types of transitions are found: bound bound, bound free, and free free. Numerical calculations are given for a rectangular GaAs quantum well in bulk ${\mathrm{Al}}_{\mathit{x}}$ ${\mathrm{Ga}}_{1\mathrm{-}\mathit{x}}$As. The absorption in this structure strongly depends on structure parameters (well thickness, mole fraction, and effective masses), and also on temperature and external magnetic field. Analysis and numerical results such as those presented here may be important for the design of infrared detectors.