External cavity GaSb-based cascade diode lasers with tuning range of 280 nm centered near 3.13 μm

Cascade type-I quantum well GaSb-based laser heterostructures with broad optical gain demonstrated tuning from 2.99 to 3.27 μm (above 35 meV) in Littrow external cavity configuration. The devices generated up to 5 mW of the narrow spectrum output power in continuous wave regime at room temperature.