The dynamical operation of scaled-down spin lasers.*

Through angular momentum conservation, injecting spin-polarized carriers in semiconductor lasers offers control of the helicity of emitted light [1,2]. This improves the operation of lasers, beyond what is possible with injecting unpolarized carriers [1] and offers paths for room-temperature spintronic applications, beyond magnetoresistance [2]. The push to scale down such spin lasers is accompanied by an enhanced contribution of spontaneous emission, usually assumed to be negligibly small. To unlock many possible applications, it is crucial that the dynamical operations and their ultrafast switching [1, 3] is investigated, including in novel operation regimes [5]. Spontaneous emission, usually assumed to be negligible, has been shown to be consequential when enhanced in the steady-state regime [4] and remains pertinent to elucidate for the dynamical operations of spin-lasers. We find various nonmonotonic trends in materials parameters on the key properties, including the helicity of the emitted light and modulation bandwidth. We provide guidance for an optimized design of scaled- down spin- lasers.

[1] M. Lindemann et al., Nature 568, 212 (2019)

[2] I. Zutic et al., Solid State Commun. 316-317, 113949 (2020)

[3] J. Lee et al., Appl. Phys. Lett. 105, 042411 (2014)

[4] G. Xu et al., Appl. Phys. Lett. 119, 171104 (2021)

[5] G. Xu et al, Appl. Phys. Lett. 122, 243501 (2023)