Fig. 5

a Total peak power change as a function of the injection current at 298 K for straight-end (blue line)/taper-end (purple line) connected to the Talbot cavity QCL array and a 2-mm-long × 10-μm-wide single laser (green line). All of the devices have no coating on both sides of the cavity. The current driver is maintained at 2 kHz with a duty circle of 0.2%. The inset is the lasing spectrum of the straight-end arrays at 1.3 times threshold current, which peaked around 4.8 μm. b The active region temperature of QCL array changing as a function of array elements interspace. The array elements ridge width is fixed as 10 μm, and the interspace changes from 0 to 20 μm with a step of 5 μm