Abstract

The recent development of vertical triple microcavities [1] opens new paths for the realization of a monolithic micro-optical parametric oscillator (OPO) and for the generation of twin or entangled photons for quantum optics applications. A vertical triple microcavity consists in three coupled planar microcavities, optically strongly coupled via 2 intermediate Bragg mirrors so that the electro-magnetic field is delocalized throughout the full nanostructure. At resonance between the three cavities, the cavity mode degeneracy is lifted, providing a triple optical resonance within each cavity. Single or multiple quantum wells placed within each cavity provide the nonlinear material. In the present work, the system consists in a MBE grown structure, made of three AlGaAs/GaAs lambda-microcavities, including single InGaAs quantum wells. In the weak light-matter coupling regime, (for high temperatures, high excitation densities, or low cavity finesse), the system only displays three cavity-like eigenstates. Alternatively, in the strong light-matter coupling regime, the three cavity modes are strongly coupled to the three exciton modes, leading to six new polariton eigenstates. It has been demonstrated that the resulting very large χ⁽³⁾ resonant nonlinearities can be used to achieve low-threshold OPO, in the weak or in the strong light-matter coupling regime [1], The photonic phase-space naturally provides triple resonance for the parametric frequencies, together with built-in cavity phase-matching for the pump, the signal and the idler. This allows easy pumping at 0°. Depending on the fine adjustment of the detuning between the cavities (the cavities are wedged and the detuning is adjusted by moving the laser spot on the sample surface), the signal and idler modes can be collected at different energies and angles.

© 2007 IEEE