Thomas Philip A, Menghrajani Kishan S, Barnes William L
Department of Physics and Astronomy, University of Exeter, Exeter, EX4 4QL, United Kingdom.
J Phys Chem Lett. 2021 Jul 29;12(29):6914-6918. doi: 10.1021/acs.jpclett.1c01695. Epub 2021 Jul 19.
Strong coupling between light and matter can occur when the interaction strength between a confined electromagnetic field and a molecular resonance exceeds the losses to the environment, leading to the formation of hybrid light-matter states known as polaritons. Ultrastrong coupling occurs when the coupling strength becomes comparable to the transition energy of the system. It is widely assumed that the confined electromagnetic fields necessary for strong coupling to organic molecules can only be achieved with external structures such as Fabry-Pérot resonators, plasmonic nanostructures, or dielectric resonators. Here we show experimentally that such structures are unnecessary and that a simple dielectric film of dye molecules supports sufficiently modified vacuum electromagnetic fields to enable room-temperature ultrastrong light-matter coupling. Our results may be of use in the design of experiments to probe polaritonic chemistry and suggest that polaritonic states are perhaps easier to realize than previously thought.
当受限电磁场与分子共振之间的相互作用强度超过向环境的损耗时，光与物质之间就会发生强耦合，从而导致形成被称为极化激元的混合光-物质态。当耦合强度变得与系统的跃迁能量相当时，就会出现超强耦合。人们普遍认为，与有机分子发生强耦合所需的受限电磁场只能通过外部结构来实现，如法布里-珀罗谐振器、等离子体纳米结构或介质谐振器。在此，我们通过实验表明，此类结构并非必要，并且一层简单的染料分子介电膜就能支持经过充分调制的真空电磁场，从而实现室温下的超强光-物质耦合。我们的结果可能有助于设计探测极化激元化学的实验，并表明极化激元态或许比之前认为的更容易实现。
