Characteristics and Thermal Control of Random and Fabry-Pérot Lasing in Nanowire Arrays

Nanolasers have attracted intense interest in the past decade because they are more compact, can be operated at higher modulation speed, and are more power-efficient than classical lasers. Thanks to these capabilities, nanolasers are now emerging for a variety of practical applications. This work presents hybrid nanolasers supporting both Fabry-Pérot and random lasing modes at room and cryogenic temperatures. These lasing modes are shown to exhibit differences in their lasing properties, such as wavelength, polarization, and coherency. New practical and broadly applicable methods are presented to distinguish these modes, including polarization-resolved measurements, near-field imaging, and photoluminescence spectroscopy measurements. Importantly, this paper demonstrates tuning between different lasing types in nanolasers, i.e., between Fabry-Pérot and random lasing. This allows the tuning of several lasing properties beyond only wavelength tuning. Thermal tuning is used here, where the Fabry-Pérot lasing modes are dominant at cryogenic temperatures, and at room temperature, random lasing becomes dominant. This work presents the first NW dual-cavity nanolaser and the first demonstration of thermal tuning between laser cavity types. As such, it provides the foundation for hybrid nanolasers, where various lasing properties can be tuned.