The parametric oscillation threshold of semiconductor microcavities in the strong coupling regime

The threshold of triply resonant optical parametric oscillation in a semiconductor microcavity in the strong coupling regime is investigated. Because of the third-order nature of the excitonic nonlinearity, a variety of different behaviours is observed thanks to the interplay of parametric oscillation and optical bistability effects. The behaviour of the signal amplitude and of the quantum fluctuations in approaching the threshold has been characterized as a function of the pump, signal and idler frequencies.