Far-Infrared Raman Laser Based On Resonant Intersubband Transitions

Artificial quantum well structures and intersubband transitions are potentially useful for far-infrared emission devices. An intersubband Raman laser has been realized in a GaAs/AlGaAs 3-level quantum-well structure. A CO2 laser in resonance with the 1-to-3 level transition is used as the pump, while the lasing emission occurs via the 3-to-2 level transition. The 1-to-2 level spacing is designed to be in resonance with the AlAs-like longitudinal optical phonon mode, making the Raman process the most favored. The emission wavelength of the Raman laser is at 15 mum. Our work presents a new mechanism for realizing intersubband lasers and opens up new possibilities in reaching the far infrared region and achieving room temperature operation.