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1. Chiral-induced circularly polarized light emission from a single-molecule junction

   https://doi.org/10.1016/j.physb.2025.417786  

   Zimbovskaya, Natalya A (September 2025, Physica B: Condensed Matter)

   In the present work we theoretically analyze electroluminescence occurring in a biased single-molecule junction with a chiral bridge imitated by a helical chain. We show that optical transitions between electron states of the chiral linker may result in the emission of circular polarized light whose handedness depends on both direction of propagation and the polarity of the bias voltage provided that the coupling between the bridge sites is sufficiently strong. The mechanism controlling this specific light emission does not depend on the magnetic moments and spin–orbit interactions. It rather relies on the chiral properties of the bridge molecule and on the distribution of the bias voltage between the electrodes in the junction. 

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2. Sub-Hertz resonance by weak measurement

   https://doi.org/https://doi.org/10.1038/s41467-020-15557-6  

   Qu, W.; Jin, S.; Sun, J.; Jiang, L.; Wen, J.; Xiao, Y. (April 2020, Nature communications)

   Weak measurement (WM) with state pre- and post-selection can amplify otherwise undetectable small signals and thus has potential in precision measurement applications. Although frequency measurements offer the hitherto highest precision due to the stable narrow atomic transitions, it remains a long-standing interest to develop new schemes to further escalate their performance. Here, we demonstrate a WM-enhanced correlation spectroscopy technique capable of narrowing the resonance linewidth down to 0.1 Hz in a room-temperature atomic vapour cell. The potential of this technique for precision measurement is demonstrated through weak magnetic-field sensing. By judiciously pre- and post-selecting frequency-modulated input and output optical states in a nearly orthogonal manner, a sensitivity of 7 fT Hz^(−1/2) at a low frequency near DC is achieved using only one laser beam with 15 µW of power. Additionally, our results extend the WM framework to a non-Hermitian Hamiltonian and shed new light on metrology and bio-magnetic field sensing. 

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3. Spin-correlated exciton–polaritons in a van der Waals magnet

   https://doi.org/10.1038/s41565-022-01204-2  

   Dirnberger, Florian; Bushati, Rezlind; Datta, Biswajit; Kumar, Ajesh; MacDonald, Allan H.; Baldini, Edoardo; Menon, Vinod M. (September 2022, Nature Nanotechnology)

   Strong coupling between light and elementary excitations is emerging as a powerful tool to engineer the properties of solid-state systems. Spin-correlated excitations that couple strongly to optical cavities promise control over collective quantum phenomena such as magnetic phase transitions, but their suitable electronic resonances are yet to be found. Here, we report strong light–matter coupling in NiPS3, a van der Waals antiferromagnet with highly correlated electronic degrees of freedom. A previously unobserved class of polaritonic quasiparticles emerges from the strong coupling between its spin-correlated excitons and the photons inside a microcavity. Detailed spectroscopic analysis in conjunction with a microscopic theory provides unique insights into the origin and interactions of these exotic magnetically coupled excitations. Our work introduces van der Waals magnets to the field of strong light–matter physics and provides a path towards the design and control of correlated electron systems via cavity quantum electrodynamics. 

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4. Hybrid microwave-optical scanning probe for addressing solid-state spins in nanophotonic cavities

   https://doi.org/10.1364/OE.417528  

   Chen, Songtao; Ourari, Salim; Raha, Mouktik; Phenicie, Christopher_M; Uysal, Mehmet_T; Thompson, Jeff_D (February 2021, Optics Express)

   Spin-photon interfaces based on solid-state atomic defects have enabled a variety of key applications in quantum information processing. To maximize the light-matter coupling strength, defects are often placed inside nanoscale devices. Efficiently coupling light and microwave radiation into these structures is an experimental challenge, especially in cryogenic or high vacuum environments with limited sample access. In this work, we demonstrate a fiber-based scanning probe that simultaneously couples light into a planar photonic circuit and delivers high power microwaves for driving electron spin transitions. The optical portion achieves 46% one-way coupling efficiency, while the microwave portion supplies an AC magnetic field with strength up to 9 Gauss at 10 Watts of input microwave power. The entire probe can be scanned across a large number of devices inside a³He cryostat without free-space optical access. We demonstrate this technique with silicon nanophotonic circuits coupled to single Er³⁺ions. 

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5. 6 nm super-resolution optical transmission and scattering spectroscopic imaging of carbon nanotubes using a nanometer-scale white light source

   https://doi.org/10.1038/s41467-021-27216-5  

   Ma, Xuezhi; Liu, Qiushi; Yu, Ning; Xu, Da; Kim, Sanggon; Liu, Zebin; Jiang, Kaili; Wong, Bryan M.; Yan, Ruoxue; Liu, Ming (November 2021, Nature Communications)

   Abstract Optical transmission and scattering spectroscopic microscopy at the visible and adjacent wavelengths denote one of the most informative and inclusive characterization methods in material research. Unfortunately, restricted by the diffraction limit of light, it cannot resolve the nanoscale variation in light absorption and scattering, diagnostics of the local inhomogeneity in material structure and properties. Moreover, a large quantity of nanomaterials has anisotropic optical properties that are appealing yet hard to characterize through conventional optical methods. There is an increasing demand to extend the optical hyperspectral imaging into the nanometer length scale. In this work, we report a super-resolution hyperspectral imaging technique that uses a nanoscale white light source generated by superfocusing the light from a tungsten-halogen lamp to simultaneously obtain optical transmission and scattering spectroscopic images. A 6-nm spatial resolution in the visible to near-infrared wavelength regime (415–980 nm) is demonstrated on an individual single-walled carbon nanotube (SW-CNT). Both the longitudinal and transverse optical electronic transitions are measured, and the SW-CNT chiral indices can be identified. The band structure modulation in a SW-CNT through strain engineering is mapped. 

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