Polarization-resolved strong light-matter coupling in planar GaAs/AlGaAs waveguides.

We study the influence of optical selection rules and polarization splittings on properties of exciton polaritons in a planar AlGaAs waveguide containing embedded GaAs quantum wells. We demonstrate that transverse electric and transverse magnetic modes couple differently with light- and heavy-hole quantum well excitons, which leads to distinct polarization splittings of the resulting polariton modes. The experimental data are in good agreement with modeling based on theoretical data for the optical selection rules for quantum well excitons.

Invalidity of Band-Gap Engineering Concept for Bi Heterovalent Doping in CsPbBr Halide Perovskite.

Heterovalent CsPbBr doping with Bi results in a significant red shift of the optical absorption of both single-crystal and powdered samples. The results of low-temperature (3.6 K) photoluminescence studies of perovskite single crystals indicate that the position of the excitonic luminescence peak remains unaffected by Bi doping that, in turn, infers that the band gap of Bi-doped perovskite is not changed as well.

Low Inhomogeneous Broadening of Excitonic Resonance in MAPbBr Single Crystals.

We present an optical study of MAPbBr single crystal grown from solution. The crystal Pm3m symmetry was confirmed by electron backscatter diffraction. Our major attention was focused on optical effects related to the excitonic states in MAPbBr.