High-power GaAs/AlGaAs quantum fountain unipolar laser emitting at 14.5 μm with 2.5% tunability

We demonstrate operation of a high-power quantum fountain unipolar laser relying on intersubband emission in optically pumped GaAs/AlGaAs quantum wells. The collected power per facet is as large as 2.3 W at 20 K and 1.5 W at 120 K, which translates into 6.6 W optical power per facet at low temperature accounting for collection efficiency. The maximum operating temperature is 135 K. We also demonstrate that the lasing wavelength can be tuned by as much as Δλ/λ≈2.5% simply by tuning the pump wavelength.