Quantum cascade lasers with monolithic air-semiconductor Bragg reflectors

Electrically pumped GaAs/AlGaAs quantum cascade lasers with monolithic one- dimensional photonic-band gap mirrors are presented. The mirrors consist of two, precisely defined grooves trenched across the laser ridge using a foc used ion beam. A substantial improvement of the laser performance is achiev ed due to the increased reflectivity of these mirrors. A decrease of the th reshold current by 40% at 150 K is observed. The maximum operation temperat ure increases from 155 K for an unmodified laser to 170 K for the laser wit h the modified mirrors, and an increase of the T-0 parameter from 99 to 114 K is found. (C) 2000 American Institute of Physics. [S0003-6951(00)00935-9 ].