Temperature performance of ring quantum-cascade laser with staircase-like distributed feedback grating

Condensed matter physics
Authors:
Papylev Denis S. Kolodeznyi Evgenii S. Babichev Andrei V. Kharin Nikita Yu. Voznyuk Gleb V. Mitrofanov Maksim I. Slipchenko Sergey O. Lyutetskii Andrey V. Evtikhiev Vadim P. Karachinsky Leonid Ya. Novikov Innokenty I. Panevin Vadim Yu. Pikhtin Nikita A. Egorov Anton Yu.
Abstract:

Direct ion-beam lithography was used to realize the staircase-like second order distributed feedback grating formed in the top cladding layers of ring quantum-cascade laser. As a result, the depth of grating slits was varied from 0.6  to 2.6 μm along the ring cavity. The whispering gallery modes lasing with near 1 kA/cm2 threshold current density at 77 K temperature was obtained with lasing wavelength close to 7.64 μm. Rise of the temperature up to 292 K yields  the multi-mode lasing near to 7.94 μm with moderate threshold current density ~4 kA/cm2. Time-resolved spectral characterization results are also discussed.