Exciton–polaritons derived from the strong light–matter interaction of an optical bound state in the continuum with an excitonic resonance can inherit an ultralong radiative lifetime and significant nonlinearities, but their realization in two-dimensional semiconductors remains challenging at room temperature. Here we show strong light–matter interaction enhancement and large exciton–polariton nonlinearities at room temperature by coupling monolayer tungsten disulfide excitons to a topologically protected bound state in the continuum moulded by a one-dimensional photonic crystal, and optimizing for the electric-field strength at the monolayer position through Bloch surface wave confinement. By a structured optimization approach, the coupling with the active material is maximized here in a fully open architecture, allowing to achieve a 100 meV photonic bandgap with the bound state in the continuum in a local energy minimum and a Rabi splitting of 70 meV, which results in very high cooperativity. Our architecture paves the way to a class of polariton devices based on topologically protected and highly interacting bound states in the continuum.

连续体中光学束缚态与激子共振的强光-物质相互作用产生的激子-极化子可以继承超长的辐射寿命和显着的非线性，但它们在室温下在二维半导体中的实现仍然具有挑战性。在这里，我们通过将单层二硫化钨激子耦合到由一维光子晶体成型的连续体中受拓扑保护的束缚态，并优化电场强度，在室温下表现出强烈的光-物质相互作用增强和大的激子-极化子非线性通过布洛赫表面波限制在单层位置。通过结构化优化方法，与活性材料的耦合在完全开放的架构中得到最大化，从而实现 100 meV 光子带隙，连续体中的束缚态处于局部能量最小值和 70 meV 的拉比分裂，这导致非常高的协作性。我们的架构为基于连续体中拓扑保护和高度相互作用的束缚态的一类极化子器件铺平了道路。