Intraband absorption of infrared radiation in a semiconductor quantum dot

The energy spectrum and bound-bound intraband transitions in semiconductor quantum dots are analyzed. Numerical results for the GaAs-${\mathrm{Al}}_{\mathrm{x}}$ ${\mathrm{Ga}}_{1\mathrm{-}\mathrm{x}}$As system indicate that a considerable absorption at a number of distinct wavelengths in the infrared range (∼7–25 μm) may be obtained, which greatly exceeds free-carrier absorption.