Ultrafast switch-off of a vertical-cavity semiconductor laser

It is shown that perturbation of an electrically pumped semiconductor vertical-cavity surface emitting laser by means of a short optical pump pulse may lead to a transient switch-off of the laser emission, provided that the pump pulse has a significantly higher photon energy than the semiconductor laser. This behavior is opposite to the commonly expected increase in emission for any laser. The unusual response is explained in terms of a transient heating of the carrier distributions, leading to a transient reduction in population at the laser mode, hence to a switch-off. Switching time constants as fast as 3 ps are observed, which is much faster than could be expected from the inverse relaxation frequency.