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The surface plasmon effect can be used to confine electromagnetic fields to a small footprint measuring tens of nanometers. The resultant resonant cavities function as optimal coherent light sources with subwavelength scale configurations. The plasmonic laser sources based on nanoshell structures, in particular, have demonstrated the potential for use in the detection of subcellular mesoscopic molecular structures. However, this structure has a high plasmon dephasing rate, which can increase the threshold of the device, making it difficult to achieve electrically excited structures, thereby rendering them unsuitable as an active component for integration into optoelectronic circuits. A different approach to confining electromagnetic fields involves using a propagating surface plasmon laser structured on a planar layered semiconductor–insulator–metal. This design enables the surface plasmon to propagate along the direction of the nanowire and offers the potential to achieve electrically driven structures by injecting current into the semiconductor nanowire. Consequently, this structure is more effective in guiding energy into integrated optoelectronic circuits compared to the isotropic radiation of nanoshell structures. However, this design also necessitates a supporting substrate, resulting in the actual device volume exceeding the nanoscale and, in some cases, even larger than the size of a cell. This limitation hinders the application of integrated optoelectronic circuits at the micro/nanoscale for bio-applications. To address these challenges, we developed a substrate-free surface plasmon polariton laser. We demonstrated that allowing direct contact between the film and the air significantly reduced the laser threshold. Furthermore, the device maintained its operational capability across different surfaces. [ABSTRACT FROM AUTHOR]

The soft and polar nature of quasi‐2D (PEA)2PbBr4 perovskite, and robust photo‐generated excitons lead exciton‐polaritons and exciton‐polarons as the important phenomena near the band edge for application in the lighting aspect. In this work, a convenient methodology is proposed based on the polariton resonant modes in temperature‐dependent (77 K to RT) spectroscopy, and investigate the effect of these quasi‐particles on refractive index dispersion. The large binding energy (≈335 meV) of quasi‐2D excitons is obtained by the reflectance measurements at 77 K. Stable exciton‐polaritons and exciton‐polarons are confirmed by energy dispersions and the observation of self‐trapped exciton‐polaron state, respectively. Furthermore, the large negative thermal‐optic coefficient due to damping effect of exciton‐phonon scattering is observed. The phenomenon is opposite to those observed in conventional semiconductors (e.g., Si, Ge, GaN, AlN, GaAs, AlAs, and ZnO etc.). The observed stable negative thermal‐optic coefficients from 160 K to RT indicate that the quasi‐2D perovskite can be used as a phase compensator for conventional semiconductor materials. [ABSTRACT FROM AUTHOR]

Semiconductor microcavities with a high quality‐factor are an important component for photonics research and technology, especially in the strong coupling regime. While van der Waals semiconductors have emerged as an interesting platform for photonics due to their strong exciton–photon interaction strength and engineering flexibility, incorporating them in photonic devices requires heterogeneous integration and remains a challenge. This study demonstrates a method to assemble high quality factor microcavities for van der Waals materials, using high reflectance top mirrors which, similar to van der Waals materials themselves, can be nondestructively and reliably peeled off the substrate and transferred onto the rest of the device. Microcavities are created with quality factors consistently above 2000 and up to 11000 ± 800; and the strong coupling regime is demonstrated. The method can be generalized to other types of heterogeneously integrated photonic structures and will facilitate research on cavity quantum electrodynamic and photonic systems using van der Waals materials. [ABSTRACT FROM AUTHOR]