Quantum dot-based tunable inversionless laser for the far infrared and terahertz ranges

A quantum dot-based laser with a frequency continuously tunable in the far-infrared and terahertz ranges via varying the optical pumping intensity is suggested. Its operation is possible at room temperature and is based on the inversionless amplification mechanism in the proposed modified three-level ladder scheme, where the pumping frequency is equal to the frequency of a dipole-forbidden transition from the ground state to the second excited state.