Publications by authors named "Joris J Carmiggelt"

Quantum sensing has developed into a main branch of quantum science and technology. It aims at measuring physical quantities with high resolution, sensitivity, and dynamic range. Electron spins in diamond are powerful magnetic field sensors, but their sensitivity in the microwave regime is limited to a narrow band around their resonance frequency.

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Nitrogen-vacancy (NV) magnetometry is a new technique for imaging spin waves in magnetic materials. It detects spin waves by their microwave magnetic stray fields, which decay evanescently on the scale of the spin-wavelength. Here, we use nanoscale control of a single-NV sensor as a wavelength filter to characterize frequency-degenerate spin waves excited by a microstrip in a thin-film magnetic insulator.

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Article Synopsis
  • Controlling magnon densities in magnetic materials can improve spin transport in devices, and this study shows how large out-of-equilibrium magnon densities are created in a thin-film magnetic insulator using microwave excitation.
  • Researchers utilize scanning-probe magnetometry with diamond electron spins to image both coherent spin waves and the resulting incoherent magnon gas, which extends hundreds of micrometers from the excitation area.
  • The findings reveal that the gas density surpasses expectations for a boson system, highlighting new avenues for manipulating spin transport and magnetic dynamics in specific directions.
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Scattering experiments have revolutionized our understanding of nature. Examples include the discovery of the nucleus [R. G.

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Spin waves-the elementary excitations of magnetic materials-are prime candidate signal carriers for low-dissipation information processing. Being able to image coherent spin-wave transport is crucial for developing interference-based spin-wave devices. We introduce magnetic resonance imaging of the microwave magnetic stray fields that are generated by spin waves as a new approach for imaging coherent spin-wave transport.

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Transition metal dichalcogenide (TMD) monolayers are two-dimensional semiconductors with two valleys in their band structure that can be selectively addressed using circularly polarized light. Their photoluminescence spectrum is characterized by neutral and charged excitons (trions) that form a chemical equilibrium governed by the net charge density. Here, we use chemical doping to drive the conversion of excitons into trions in [Formula: see text] monolayers at room temperature, and study the resulting valley polarization via photoluminescence measurements under valley-selective optical excitation.

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