Interband Cascade Lasers with Wavelengths Spanning 2.9 m to 5.2 m

We report an experimental investigation of four interband cascade lasers with wavelengths spanning the mid-infrared spectral range, i.e., 2.9 m to 5.2 m, near room temperature in pulsed mode. One broad-area device had a pulsed threshold current density of only 3.8 A/cm at 78 K ( = 3.6 m) and 590  A/cm at 300 K ( = 4.1 m). The room-temperature threshold for the shortest-wavelength device ( = 2.6 m to 2.9 m) was even lower, 450 A/cm. A␣cavity-length study of the lasers emitting at 3.6 m to 4.1 m yielded an internal loss varying from 7.8 cm at 78 K to 24 cm at 300 K, accompanied by a decrease of the internal efficiency from 77% to 45%.