Spin-vertical-cavity surface-emitting lasers with by-design-defined birefringence for high-speed modulation

We propose a new, to the best of our knowledge, type of spin-vertical-cavity surface-emitting laser (VCSEL) with controlled by design birefringence. To this aim, we utilize the so-called columnar thin films (CTFs) in the VCSEL dielectric distributed Bragg mirror and/or in a second dielectric cavity. We design such CTF-VCSELs with pre-defined birefringence and calculate their polarization-resolved resonant longitudinal modes and the corresponding quantum-well confinement factors and threshold gains. Using the spin-flip VCSEL model, we show that such spin CTF-VCSELs can achieve small-signal modulation response with a 3 dB cutoff frequency of several hundreds of GHz.