We demonstrate the temporal evolution of terahertz (THz) wave propagation in one-dimensional periodic dielectrics. Distributed Bragg reflectors and a resonant cavity are investigated: The structures involve air gaps interleaved between polymer films. Transmitted and reflected broadband THz waves are measured by means of THz time-domain spectroscopy. The experimental results agree well with transfer matrix calculations.
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http://dx.doi.org/10.1364/ao.45.001857 | DOI Listing |
We treat edge-mode resonance that may exist at boundaries of transversely finite beams illuminating a photonic lattice. The lattice is in the dark state signifying a perfect bound state in the continuum (BIC). The dark state is non-radiative in symmetric systems because lateral waves cannot couple to the lattice due to destructive interference between counter-propagating waves.
View Article and Find Full Text PDFPhys Rev Lett
December 2024
Université Grenoble Alpes, Grenoble INP, CEA, IRIG, PHELIQS, 38000 Grenoble, France.
The antiferromagnetic structure of Yb_{3}Ga_{5}O_{12} is identified by neutron diffraction experiments below the previously known transition at T_{λ}=54 mK. The magnetic propagation vector is found to be k=(1/2,1/2,0), an unusual wave vector in the garnet structure. The associated complex magnetic structure highlights the role of exchange interactions in a nearly isotropic system dominated by dipolar interactions and finds echoes with exotic structures theoretically proposed.
View Article and Find Full Text PDFPhys Rev Lett
December 2024
Université Grenoble Alpes, CEA, Grenoble INP, IRIG-PHELIQS, F-38000 Grenoble, France.
We experimentally study the evolution of the magnetic moment m and exchange interaction J as a function of hydrostatic pressure in the zero-field helimagnetic phase of the strongly correlated electron system MnSi. The suppression of magnetic order at ≈1.5 GPa is shown to arise from the J collapse and not from a quantum fluctuations induced reduction of m.
View Article and Find Full Text PDFJ Vis Exp
December 2024
CFD Research Corporation;
Military personnel involved in weapon training are subjected to repeated low-level blasts. The prevailing method of estimating blast loads involves wearable blast gauges. However, using wearable sensor data, blast loads to the head or other organs cannot be accurately estimated without knowledge of the service member's body posture.
View Article and Find Full Text PDFPNAS Nexus
December 2024
School of Civil Engineering, University of Sydney, Sydney, NSW 2006, Australia.
Disordered hyperuniform materials are increasingly drawing attention due to their unique physical properties, associated with global isotropy and locally broken orientational symmetry, that set them apart from traditional crystalline materials. Using a dynamic space-partitioning process, we generate disordered hyperuniform cellular structures where distinct patterns of pentagonal and heptagonal topological defects emerge within hexagonal domains. The microscopic defect dynamics are guided by local topological transitions, commonly observed in viscoelastic systems.
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