Toward ultrafast spin lasers?

Injecting spin-polarized carriers in semiconductor lasers provides operating principles for room temperature spintronic devices not limited to magnetoresistance. Important steady-state properties have been demonstrated in these lasers, including threshold reduction [1] and spin amplification [2]. However, their main advantage is dynamical operation, predicted to have an enhanced modulation bandwidth, improved switching, and faster operation than the conventional lasers (with spin-unpolarized carriers) [3-5]. As these predictions are being verified [6,7], we provide a generalized description of spin lasers to interpret related experiments and understand the limiting factors for their operation. [1] J. Rudolph, et al., Appl. Phys. Lett. 87, 241117 (2005). [2] S. Iba, et al., Appl. Phys. Lett. 98, 081113 (2011). [3] P. E. Faria Junior, G. Xu, J. Lee, N. C. Gerhardt, G. M. Sipahi, and I. Zutic, Phys. Rev. B 92, 075311 (2015). [4] J. Lee, R. Oszwaldowski, C. Gothgen, and I. Zutic, Phys. Rev.B 85, 045314 (2012). [5] E. Wasner,S. Bearden, J. Lee and I. Zutic, Appl. Phys. Lett. 107, 082406 (2015). [6] M. Lindemann, T. Pusch, R. Michalzik, N. C. Gerhardt,and M. R. Hofmann, Appl. Phys. Lett. 108, 042404 (2016). [7] H. Hopfner, et al., Appl. Phys. Lett. 104, 022409 (2014).