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Creators/Authors contains: "Shen, Yi"

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  1. We introduce a reflection-mode diffraction tomography technique that enables the simultaneous recovery of forward- and backward-scattering information for high-resolution 3D refractive index reconstruction. Our technique works by imaging a sample on a highly reflective substrate and employing a multiple-scattering model and a reconstruction algorithm. It combines the modified Born series as the forward model, Bloch and perfect electric conductor boundary conditions to handle oblique incidence and substrate reflections, and the adjoint method for efficient gradient computation in solving the inverse-scattering problem. We validate the technique through simulations and experiments, achieving accurate reconstructions in samples with high refractive index contrasts and complex geometries. Forward scattering captures smooth axial features, while backward scattering reveals complementary interfacial details. Experimental results on dual-layer resolution targets, 3D randomly distributed beads, phase structures obscured by highly scattering fibers, fixed breast cancer cells, and fixedC. elegansdemonstrate its robustness and versatility. This technique holds promise for applications in semiconductor metrology and biomedical imaging. 
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  2. Free, publicly-accessible full text available January 1, 2026
  3. Achieving ultranarrow absorption linewidths in the condensed phase enables optical state preparation of specific non-thermal states, a prerequisite for quantum-enabled technologies. 
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    Free, publicly-accessible full text available August 7, 2025
  4. A nickel bromide complex supported by a non-innocent ferrocene-chelating heteroscorpionate ligand, [(fc(PPh2)(BH(3,5-Me2pz)2)NiBr)] ((fcP,B)NiBr, fc = 1,1′-ferrocenediyl, pz = pyrazole), was synthesized and characterized. 
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  5. The energetic disorder induced by fluctuating liquid environments acts in opposition to the precise control required for coherence-based sensing. Overcoming fluctuations requires a protected quantum subspace that only weakly interacts with the local environment. We report a ytterbium complex that exhibited an ultranarrow absorption linewidth in solution at room temperature with a full width at half maximum of 0.625 milli–electron volts. Using spectral hole burning, we measured an even narrower linewidth of 410 pico–electron volts at 77 kelvin. Narrow linewidths allowed low-field magnetic circular dichroism at room temperature, used to sense Earth-scale magnetic fields. These results demonstrated that ligand protection in lanthanide complexes could substantially diminish electronic state fluctuations. We have termed this system an “atomlike molecular sensor” (ALMS) and proposed approaches to improve its performance. 
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    Free, publicly-accessible full text available August 9, 2025