Genco Armando, Louca Charalambos, Cruciano Cristina, Song Kok Wee, Trovatello Chiara, Di Blasio Giuseppe, Sansone Giacomo, Randerson Sam A, Claronino Peter, Georgiou Kyriacos, Jayaprakash Rahul, Watanabe Kenji, Taniguchi Takashi, Lidzey David G, Kyriienko Oleksandr, Dal Conte Stefano, Tartakovskii Alexander I, Cerullo Giulio
Dipartimento di Fisica, Politecnico di Milano, Piazza Leonardo Da Vinci 32, 20133, Milano, Italy.
NanoPhotonics Centre, Cavendish Laboratory, Department of Physics, JJ Thompson Ave, University of Cambridge, Cambridge, UK.
Nat Commun. 2025 Jul 14;16(1):6490. doi: 10.1038/s41467-025-61607-2.
Ultrafast all-optical logic devices based on nonlinear light-matter interactions hold the promise to overcome the speed limitations of conventional electronic devices. Strong coupling of excitons and photons inside an optical resonator enhances such interactions and generates new polariton states which give access to unique nonlinear phenomena, such as Bose-Einstein condensation, used for all-optical ultrafast polariton transistors. However, to reach the threshold for condensation high quality factors and high pulse energies are required. Here we demonstrate all-optical switching exploiting the ultrafast transition from the strong to the weak coupling regime in low-Q microcavities embedding bilayers of transition metal dichalcogenides with high optical nonlinearities and fast exciton relaxation times. We observe a collapse of polariton gaps as large as 55 meV, and their revival, lowering the threshold for optical switching below 4 pJ per pulse, while retaining ultrahigh switching frequencies. As an additional degree of freedom, the switching can be triggered pumping either the intra- or the interlayer excitons of the bilayers at different wavelengths, speeding up the polariton dynamics, owing to unique interspecies excitonic interactions. Our approach will enable the development of compact ultrafast all-optical logical circuits and neural networks, showcasing a new platform for polaritonic information processing based on manipulating the light-matter coupling.
基于非线性光与物质相互作用的超快全光逻辑器件有望克服传统电子器件的速度限制。光学谐振腔内激子与光子的强耦合增强了这种相互作用，并产生了新的极化激元态，从而能够实现独特的非线性现象，如用于全光超快极化激元晶体管的玻色-爱因斯坦凝聚。然而，要达到凝聚阈值，需要高品质因数和高脉冲能量。在此，我们展示了一种全光开关，它利用了低Q微腔中从强耦合到弱耦合状态的超快转变，该微腔嵌入了具有高光非线性和快速激子弛豫时间的过渡金属二卤化物双层。我们观察到高达55毫电子伏特的极化激元能隙崩塌及其恢复，将光开关阈值降低到每个脉冲低于4皮焦耳，同时保持超高的开关频率。作为一个额外的自由度，通过在不同波长泵浦双层的层内或层间激子来触发开关，由于独特的种间激子相互作用，可以加快极化激元动力学。我们的方法将推动紧凑型超快全光逻辑电路和神经网络的发展，展示了一个基于操纵光与物质耦合的极化激元信息处理新平台。
