Seminarium Optyczne

The search for material platforms that ensure low cost, ease of fabrication, usability (room temperature) and nonlinearity in the same device is a serious challenge for today's photonics. Our work presents a first step towards a major breakthrough in the field of perovskite integrated photonics. For this purpose, we developed a versatile, template-assisted method for fabricating perovskite microstructures of any arbitrary, pre-defined shape. Our structures demonstrate waveguiding capabilities and facilitate the formation of spatially extended condensates of coherent exciton-polaritons. Our microwires, characterized by their ability to bend without compromising optical quality, are formed from CsPbBr3 crystals and can be deposited on any substrate, enhancing compatibility with existing photonic devices. Notably, our method overcomes the limitations of traditional waveguiding setups by eliminating the need for extrinsic cavity mirrors. Our approach significantly simplifies the fabrication process, making on-chip polaritonic devices more accessible and cost-effective.We demonstrate polariton lasing from the interfaces and corners of the microwires, with large blueshifts observed with excitation power. The high mutual coherence between different edge and corner lasing signals, evidenced in the far-field photoluminescence and angle-resolved spectroscopy, indicates the formation of a coherent, extended over macroscopic distance polariton condensate. This condensate is capable of propagating over long distances within the wires and even coupling between neighbouring wires through air-gaps. Perovskite crystals can also be enclosed in photonic microcavity composed of two Bragg mirrors and, additionally,the cavity can be filled with a highly birefringent liquid crystal. The birefringence is controlled by external electric field which allows to drive the system through wide range of H-V split photonic modes and spin-orbit coupled modes of Rashba-Dresselhaus type. The strong light-matter coupling condition is achieved with subsequent cavity modes, what allow us to observe non-linear effect at low threshold powers. The polariton lasing at room temperature is revealed in all regimes, including chiral lasing from circularly polarized polariton bands. The simplicity and scalability of our platform, combined with its compatibility with standard photonic components,pave the way for future large-scale, integrated polaritonic circuitry. Our findings not only demonstrate the potential of CsPbBr3 perovskites in photonic applications but also provide a more accessible path for the development of advanced on-chip optical devices with built-in nonlinearities.