A research team from Skoltech and ITMO university, led by Professor Pavlos Lagoudakis, the director of the Center for Photonic Science and Engineering at Skoltech, a laureate of the Vyzov (Challenge) prize, has obtained tunable polariton emission at room temperature on CsPbBr3 perovskite crystals as a promising platform for integration into lateral microchips — a new concept for the integrated all-optical logic, which Skoltech researchers are working on. The research results are presented in the Advanced Optical Materials journal. The research was supported by Russian Science Foundation’s grant No. 23-72-00059 titled “Optical lateral logic gates based on polariton condensates in perovskite films.”

Exciton-polaritons are hybridised states of light and matter, which are formed as a result of strong interaction of optical modes of microcavity — photons — with elementary excitations of a material — excitons. The realization of polaritons in conventional semiconductor materials such as GaAs requires cryogenic temperatures due to the low binding energy of excitons in these materials. Previous room temperature polaritonic research by the laboratory has been predominantly focused on specialized organic polymer materials with limited resources. In the present work, the inorganic halide perovskite CsPbBr3, characterized by high exciton binding energy, optical stability and excellent lattice homogeneity, was investigated as an alternative.

“The new work is a study of fundamental characteristics that open new horizons for applications: the possibility of obtaining tunable polariton emission at a wavelength of more than 23 nm in the green region of the optical spectrum at room temperature. The emission spectrum was tunable by changing the effective length of the planar multi-λ microcavity using a point squeeze device, without changing the crystal position relative to the pump beam. The possibility of wide spectral tunability of polariton emission confirms the versatility of CsPbBr3 as a platform for promising technological developments, including integration into optical logic,” commented Maxim Kolker, the lead author of the study, a research intern at the Photonics Center’s Laboratory of Hybrid Photonics and a PhD student at the “Physics” program at Skoltech.

In the era of rapid technological change, this breakthrough represents a significant step forward. The prospect of developing high-speed all-optical polaritonic logic devices is causing great excitement among scientists and the technology community. This discovery inspires researchers to pursue new results and discoveries.