Strong coupling and polariton condensation in a monolithic optical microcavity with position-dependent quantum well properties

Monolithic semiconductor optical microcavities for cavity polaritons are typically grown with position-dependent properties, enabling the probing of different exciton-photon energy detunings within a single sample. Normally, it is done by inducing a cavity thickness gradient across the sample during growth. Here, we present an alternative approach in which the microcavity is grown with the quantum wells’ emission wavelength that varies as a function of position on the sample. At the same time, the cavity resonance remains virtually constant across the wafer. We present evidence for strong exciton-photon coupling and demonstrate polariton condensation. Our approach enables wide tunability of detuning while keeping a relatively small energy shift of the lower polariton branch, which can be beneficial in experiments using quasi-resonant excitation.