Spin vertical-cavity surface-emitting lasers with linear gain anisotropy: Prediction of exceptional points and nontrivial dynamical regimes

It is shown that when the linear gain anisotropy is properly accounted for, spin-injected vertical-cavity surface-emitting lasers (spin-VCSELs) offer interesting functionalities. Using the extended spin-flip model (SFM), we predict the existence of exceptional points (EPs) in spin-VCSELs and two interesting phenomena which accompany EPs, namely, (i) the polarization switching manifesting as induced change of field helicity sign and (ii) frequency comb generation without the need of external injection locking. Both effects have tremendous technological potential such as fast on-chip polarization switching, and most importantly, their concepts are not limited only to spin-VCSEL technology. We discuss the concept of anisotropy-engineered non-Hermitian microlasers and we provide a theoretical background to study their polarization dynamics near EPs.