Monolithically integrated terahertz quantum cascade array laser

By integrating triple terahertz quantum cascade lasers (at ~3.25 THz) monolithically into an array, a peak power of 213 mW is obtained at 10 K with a threshold current density of only 257 A/cm². The device shows distinct single-lobe far-field behaviour in the temperature range from 10 to 90 K, with a full-width at half-maximum of 36°. The highest operating temperature of the array laser is identical to that of the single ridge laser, indicating good heat dissipation design in the array. These results are promising for realising high power THz quantum cascade lasers.