Researchers provide experimental evidence of intrinsic linewidths approaching the quantum limit in a GaAs/AlGaAs quantum cascade laser emitting at 2.5 THz. Despite the expected dominant broadening effect induced by thermal photons, the measured intrinsic linewidth is 90 Hz — even narrower than that of a semiconductor laser working at significantly shorter wavelengths.
- Miriam S. Vitiello
- Luigi Consolino
- Paolo De Natale
