Vacuum-field Rabi splitting in quantum-well infrared photodetectors

The vacuum-field Rabi splitting due to bound-to-quasibound intersubband transitions in GaAs quantum wells has been demonstrated. A waveguide was designed and the infrared light was resonantly coupled inside with a prismlike technique. Reflection and photocurrent spectra show sharp Rabi doublets. The infrared detectivity of such a structure was investigated with temperature. We have proved that the vacuum-field Rabi splitting of intersubband absorption is easy to observe and has potential applications in optoelectronic devices.