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In this work, the momentum mismatching based on which the acousto-optic (AO) transfer function and diffraction efficiency was acquired, was calculated considering the properties of AO crystals in AO interactions in acousto-optic tunable filter (AOTF). Transfer functions were obtained using a 4f optical system combined with AOTF and compared with theoretical calculations. It demonstrated the influence of acoustic energy shift on the AO interaction which should be considered in the design of AOTF.
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http://dx.doi.org/10.1364/OE.514490 | DOI Listing |
Sci Adv
July 2025
Department of Physics, Tsinghua University, Beijing 100084, China.
The silicon-based field-effect transistor (FET) is approaching the physical limits for the prominent short-channel effects and the sequent leakage currents under the conventional paradigm. Here, we propose a momentum-dependent field-effect transistor (MD-FET) to address this issue, in which a monolayer 2D semiconductor is sandwiched by two cross 1D carbon nanotube electrodes. The MD-FET enables a perfect off state, as the elastic tunneling is forbidden by the momentum mismatch between the cross 1D contacts.
View Article and Find Full Text PDFProc Natl Acad Sci U S A
July 2025
CNRS, Ecole Centrale de Lyon, Institut National des Sciences Appliquées de Lyon, Universite Claude Bernard Lyon 1, Laboratoire de Mécanique des Fluides et d'Acoustique, UMR 5509, Ecully 69130, France.
The interplay between viscous and frictional dissipation is key to understanding quantum turbulence dynamics in superfluid He. Based on a coarse-grained two-fluid description, an original scale-by-scale energy budget that identifies each scale's contribution to energy dissipation is derived. Using the Hall-Vinen-Bekharevich-Khalatnikov (HVBK) model to further characterize mutual friction, direct numerical simulations at temperatures 1.
View Article and Find Full Text PDFNano Lett
July 2025
State Key Laboratory of Optoelectronic Materials and Technologies, Guangdong Province Key Laboratory of Display Material and Technology, and School of Electronics and Information Technology, Sun Yat-sen University, Guangzhou 510275, China.
Hyperbolic phonon polaritons (HPhPs) in polar van der Waals crystals, such as α-MoO and α-VO, enable deep subwavelength light confinement and in-plane manipulation via hyperbolic dispersion, yet momentum mismatch hinders efficient excitation. We present a far-field method to excite in-plane HPhPs using plasmonic gold nanorods. Surface plasmon resonance (SPPR) in nanorods mediates strong interactions between free-space waves and HPhPs in α-MoO.
View Article and Find Full Text PDFOptical bound states in the continuum (BICs) are widely studied in photonics and metasurfaces for their high-quality () resonances, which underpin applications in sensing, lasing, and nonlinear optics. While much is known about symmetry-protected BICs, which arise from mismatches in profile symmetry with the continuum, Friedrich-Wintgen BICs (FWBICs)-formed by total destructive interference of multiple leaky modes-are inherently less predictable and remain understudied. Topologically, BICs are characterized as polarization singularities in momentum space, and their dynamic evolution (e.
View Article and Find Full Text PDFNat Commun
May 2025
Photonic Systems Laboratory (PHOSL), STI-IEM, École Polytechnique Fédérale de Lausanne, CH-1015, Lausanne, Switzerland.
Quasi-phase-matching (QPM) is a widely adopted technique for mitigating stringent momentum conservation in nonlinear optical processes such as second-harmonic generation (SHG). It effectively compensates for the phase velocity mismatch between optical harmonics by introducing a periodic spatial modulation to the nonlinear optical medium. Such a mechanism has been further generalized to the spatiotemporal domain, where a non-stationary spatial QPM can induce a frequency shift of the generated light.
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