Publications by authors named "Hengjun Chen"

Article Synopsis
  • Chiroptical metasurfaces are innovative materials designed to control how light's polarization behaves, allowing for real-time adjustments and extensive manipulation of light properties.* -
  • This study introduces a dielectric metasurface made from LiNbO that features an active electro-optic tuning ability, achieving a significant circular dichroism (CD) of 0.89 and a high Q-factor of 9.3 × 10 at a specific wavelength.* -
  • The metasurface can modulate CD up to 0.83 with remarkable sensitivity, offering a wide range of tunable polarization states, making it a promising option for advanced electro-optic applications.*
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A new laser system has been developed to generate coherent deep ultraviolet (DUV) radiation at 272 nm. The DUV lasers were produced via intra-cavity frequency doubling of the : lasers emitting fundamentally at 544 nm. Continuous-wave (cw) and -switched operations were performed with a type I phase-matched - nonlinear crystal.

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We report on the efficient high-power operation of a laser-diode-pumped Er-doped yttrium aluminum perovskite (Er:YAP) laser in the 3 m spectral region at room temperature. 6.9 W of continuous-wave (CW) output power was obtained at 2920 nm.

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Potassium terbium fluoride (KTF) crystal is a promising magneto-active material for creating multi-kilowatt average-power Faraday isolators operating at the visible and near-infrared wavelengths. Nevertheless, the key material's parameter needed for the design of any Faraday isolator-the Verdet constant, has not been comprehensively investigated yet. In this Letter, we report on measurement of the Verdet constant of the KTF crystal for wavelengths between 600 and 1500 nm and for temperatures ranging from 15 to 295 K.

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We report laser operation of Pr:YAlO pumped by a frequency-doubled optically pumped semiconductor laser. Continuous-wave laser oscillations at around 622 nm, 662 nm, and 747 nm were demonstrated in plano-concave or/and plano-plano cavities. The maximum slope efficiencies were found to be 37%, 35%, and 59%, respectively, which are record-high values for Pr:YAlO lasers.

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A dual stimuli-responsive system was constructed by introducing methyl viologen into a luminescent europium-organic framework with a compact packing mode. In addition to absorption and emission properties that are sensitive to both light and heat involving electron/energy transfer processes, the photoactive MOF has a spectral response from UV to the visible region.

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A new type of electron transfer (ET) system was built via the combination of a highly stable MOF host framework and methyl viologen guest molecule. The π-stacking arrangements adjust the distance between the D-A components, contributing to the formation of an ultra long-lived charge separated state in the photo/thermo dual stimuli-responsive complex.

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