Simultaneous three-state lasing in quantum dot laser at room temperature

The first quantum dot laser under simultaneous three-state lasing operation at room temperature has been realised. The device exhibits ground state lasing at 1306 nm, the fist excited state lasing at 1213 nm and the second excited state lasing at 1152 nm synchronously. This is attributed to the long carrier relaxation time from higher energy levels to lower energy levels.