{"title":"Observation of Floquet states and their dephasing in colloidal nanoplatelets driven by visible pulses","authors":"Yuxuan Li, Yupeng Yang, Yuan Liu, Jingyi Zhu, Kaifeng Wu","doi":"10.1038/s41566-024-01505-z","DOIUrl":null,"url":null,"abstract":"Coherent interaction between light and matter generates photon-dressed replicas of the original electronic levels (that is, Floquet states). This opens up a so-called field of Floquet engineering that applies electromagnetic fields to create new non-equilibrium phases of solid-state materials. The direct observation of such Floquet states, which often requires low-temperature, high-vacuum housing of the interrogated materials and low-energy infrared photons or microwaves as the driver, has been challenging. Here we report the observation of Floquet states in CdSe nanoplatelets, which are the colloidal analogue of quantum wells, under ambient conditions using femtosecond transient absorption. A sub-bandgap visible photon dresses a heavy-hole state (|hh1〉) to a Floquet state (|hh1 + ℏωL〉) that can hybridize with the first quantized electron state (|e1〉). This enables us to probe the Floquet state using a near-infrared photon through its transition to the second quantized electron state (|e2〉). Dephasing of the Floquet state into the real population of |e1〉 is also directly observed with a dephasing time of a few hundred femtoseconds, which is well reproduced by our density matrix simulations. Researchers demonstrate the ambient-condition observation of Floquet states in CdSe nanoplatelets, a colloidal analogue of quantum wells.","PeriodicalId":18926,"journal":{"name":"Nature Photonics","volume":null,"pages":null},"PeriodicalIF":32.3000,"publicationDate":"2024-08-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Nature Photonics","FirstCategoryId":"101","ListUrlMain":"https://www.nature.com/articles/s41566-024-01505-z","RegionNum":1,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q1","JCRName":"OPTICS","Score":null,"Total":0}
引用次数: 0
Abstract
Coherent interaction between light and matter generates photon-dressed replicas of the original electronic levels (that is, Floquet states). This opens up a so-called field of Floquet engineering that applies electromagnetic fields to create new non-equilibrium phases of solid-state materials. The direct observation of such Floquet states, which often requires low-temperature, high-vacuum housing of the interrogated materials and low-energy infrared photons or microwaves as the driver, has been challenging. Here we report the observation of Floquet states in CdSe nanoplatelets, which are the colloidal analogue of quantum wells, under ambient conditions using femtosecond transient absorption. A sub-bandgap visible photon dresses a heavy-hole state (|hh1〉) to a Floquet state (|hh1 + ℏωL〉) that can hybridize with the first quantized electron state (|e1〉). This enables us to probe the Floquet state using a near-infrared photon through its transition to the second quantized electron state (|e2〉). Dephasing of the Floquet state into the real population of |e1〉 is also directly observed with a dephasing time of a few hundred femtoseconds, which is well reproduced by our density matrix simulations. Researchers demonstrate the ambient-condition observation of Floquet states in CdSe nanoplatelets, a colloidal analogue of quantum wells.
期刊介绍:
Nature Photonics is a monthly journal dedicated to the scientific study and application of light, known as Photonics. It publishes top-quality, peer-reviewed research across all areas of light generation, manipulation, and detection.
The journal encompasses research into the fundamental properties of light and its interactions with matter, as well as the latest developments in optoelectronic devices and emerging photonics applications. Topics covered include lasers, LEDs, imaging, detectors, optoelectronic devices, quantum optics, biophotonics, optical data storage, spectroscopy, fiber optics, solar energy, displays, terahertz technology, nonlinear optics, plasmonics, nanophotonics, and X-rays.
In addition to research papers and review articles summarizing scientific findings in optoelectronics, Nature Photonics also features News and Views pieces and research highlights. It uniquely includes articles on the business aspects of the industry, such as technology commercialization and market analysis, offering a comprehensive perspective on the field.