Fig. 1: Open cavity hosting quasi-2D perovskite and strong coupling condition.
From: Room-temperature polariton condensate in a quasi-2D hybrid perovskite
a Two distributed Bragg reflectors (DBRs) on separate piezo stages form an open optical microcavity with tunable resonance. The upper mirror contains planar sections and sphere cap shaped indentations. The active material is a mechanically exfoliated, fully hBN-encapsulated quasi-2D halide perovskite (HaP) flake. b (top) Photoluminescence (PL) spectrum of a 218 nm thick n = 3 quasi-2D HaP crystal excited at 532 nm (CW laser) containing some admixture from n = 4 layers. (bottom) Structure of the quasi-2D HaP with n = 3. c White light reflectivity spectra as a function of the cavity air gap at normal incidence (\({k}_{\parallel }=0\)). From a coupled oscillator model (dashed lines) we deduce a light-matter coupling strength of \(g=23.5\;{{\rm{meV}}}\) for the n = 3 quasi-2D HaP exciton at 2 eV.
