Electronic frequency mixers are fundamental building blocks of electronic systems. Harmonic frequency mixing in particular enables broadband electromagnetic signal analysis across octaves of spectrum using a single local oscillator. However, conventional harmonic frequency mixers do not operate beyond hundreds of gigahertz to a few terahertz. If extended to the petahertz scale in a compact and scalable form, harmonic mixers would enable field-resolved optical signal analysis spanning octaves of spectra in a monolithic device without the need for frequency conversion using nonlinear crystals. Here, we demonstrate lightwave-electronic harmonic frequency mixing beyond 0.350 PHz using plasmonic nanoantennas. We demonstrate that the mixing process enables complete, field-resolved detection of spectral content far outside that of the local oscillator, greatly extending the range of detectable frequencies compared to conventional heterodyning techniques. Our work has important implications for applications where optical signals of interest exhibit coherent femtosecond-scale dynamics spanning multiple harmonics.
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http://dx.doi.org/10.1126/sciadv.adq0642 | DOI Listing |
Cortex
December 2024
Institute of Research in Psychology (IPSY) & Institute of Neuroscience (IoNS), Louvain Bionics Center, University of Louvain (UCLouvain), Louvain-la-Neuve, Belgium; School of Health Sciences, HES-SO Valais-Wallis, The Sense Innovation and Research Center, Lausanne & Sion, Switzerland. Electronic address:
Effective social communication depends on the integration of emotional expressions coming from the face and the voice. Although there are consistent reports on how seeing and hearing emotion expressions can be automatically integrated, direct signatures of multisensory integration in the human brain remain elusive. Here we implemented a multi-input electroencephalographic (EEG) frequency tagging paradigm to investigate neural populations integrating facial and vocal fearful expressions.
View Article and Find Full Text PDFHealthcare (Basel)
January 2025
Department of Computer Science, Institute of Mathematics and Statistics, University of São Paulo (USP), São Paulo 05508-220, SP, Brazil.
Background/objectives: The aim of this paper was to compare voice and speech characteristics between post-COVID-19 and control subjects. The hypothesis was that acoustic parameters of voice and speech may differentiate subjects infected by COVID-19 from control subjects. Additionally, we expected to observe the persistence of symptoms in women.
View Article and Find Full Text PDFJ Biomech Eng
January 2025
School of Aerospace and Mechanical Engineering, University of Oklahoma, 865 Asp Ave, Norman, OK 73019, USA.
Hearing loss is highly related to acoustic injuries and mechanical damage of ear tissues. The mechanical responses of ear tissues are difficult to measure experimentally, especially cochlear hair cells within the organ of Corti (OC) at microscale. Finite element (FE) modeling has become an important tool for simulating acoustic wave transmission and studying cochlear mechanics.
View Article and Find Full Text PDFLight Sci Appl
January 2025
Department of Physics, University of Ottawa, Ottawa, ON, K1N 6N5, Canada.
Graphene has unique properties paving the way for groundbreaking future applications. Its large optical nonlinearity and ease of integration in devices notably makes it an ideal candidate to become a key component for all-optical switching and frequency conversion applications. In the terahertz (THz) region, various approaches have been independently demonstrated to optimize the nonlinear effects in graphene, addressing a critical limitation arising from the atomically thin interaction length.
View Article and Find Full Text PDFJ Chem Phys
January 2025
State Key Laboratory of Physical Chemistry of Solid Surfaces, Collaborative Innovation Center of Chemistry for Energy Materials, Fujian Provincial Key Laboratory of Theoretical and Computational Chemistry, and Department of Chemistry, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen 361005, People's Republic of China.
Vibro-polaritons are hybrid light-matter states that arise from the strong coupling between the molecular vibrational transitions and the photons in an optical cavity. Developing theoretical and computational methods to describe and predict the unique properties of vibro-polaritons is of great significance for guiding the design of new materials and experiments. Here, we present the ab initio cavity Born-Oppenheimer density functional theory (CBO-DFT) and formulate the analytic energy gradient and Hessian as well as the nuclear and photonic derivatives of dipole and polarizability within the framework of CBO-DFT to efficiently calculate the harmonic vibrational frequencies, infrared absorption, and Raman scattering spectra of vibro-polaritons as well as to explore the critical points on the cavity potential energy surface.
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