Current- and temperature-induced beam steering in 7.8-µm emitting quantum-cascade lasers

We report large current- and temperature-induced beam-steering effects, observed in the far-field distribution of InP-based quantum-cascade lasers emitting around 7.8-µm wavelength operated in pulsed mode Changing the temperature within a narrow range of about 10 °C around room-temperature leads to a change in the direction of the output beam, as given by the central lobe in the far-field intensity distribution, from +11° to -13° as measured relative to the resonator axis. This beam steering effect is linked to changes in the lateral mode distribution, as revealed by time-resolved spectroscopy of the lasing spectrum.