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Mechanically tunable broadband terahertz modulator based on high-aligned Ni nanowire arrays
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We present a mechanically tunable broadband terahertz(THz) modulator based on the high-aligned Ni nanowire(NW)arrays. The modulator is a sandwich structure consisting of two polydimethylsiloxane layers and a central layer of highaligned Ni NW arrays. Our experimental measurements reveal the transmittance of THz wave can be effectively modulated by mechanical stretching. The NW density in arrays increases with the strain increasing, which induced an enhancement in the absorption of THz wave. When the strain increases from 0 to 6.5%, a linear relationship is observed for the variation of modulation depth(MD) of THz wave regarding the strain, and the modulated range is from 0 to 85% in a frequency range from 0.3 THz to 1.8 THz. Moreover, the detectable MD is about 15% regarding the 1% strain change resolution. This flexible Ni NW-based modulator can be promised many applications, such as remote strain sensing, and wearable devices. 相似文献
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We investigate the diffusion interaction and quantitative analysis of zinc dialkyldithiophosphate (ZDDP) mixed with lube base oil (LBO) at different concentrations using terahertz time-domain spectroscopy (THzTDS).When the concentration exceeds 6.78%,the characteristic absorption peaks exhibit significantly shift,and the absorption coefficient peak value is nonlinear against concentration.Moreover,the absorption coefficients of mixed samples follow the Beer’s law at a concentration below 6.78%.The quantitative analysis enables a strategy for monitoring the formulation of lubricating oil in real time. 相似文献
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IntroductionThestudyofsymmetryandconservedquantityofmechanicalsystemisanimportanttopicinmathematics,mechanicsandphysics .ThemoderntheoriesofsymmetryandconservedquantityofmechanicalsystemincludeNoethersymmetrytheoryandLiesymmetrytheory .In 1979M .Lutzkyando… 相似文献
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We report the fast lateral photovoltaic effect in pure congruent LiNbO3 crystal induced by pulsed laser and continuous wave laser with wavelengths of 355, 532, and 1064 nm. A typical ultrafast photovoltage can be observed on the surface perpendicular to the c axis, With the rise time of 1.5 ns and the full-width at half-maximum of 1-2 ns, when the laser pulse inhomogeneously irradiates on the crystal. The peak open-circuit photovoltages show a linear dependence on the incident laser intensities. The mechanism of the photovoltaic characteristics is proposed. 相似文献
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Consistency-dependent optical properties of lubricating grease studied by terahertz spectroscopy
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The optical properties of four kinds of lubricating greases (urea, lithium, extreme pressure lithium, molybdenum disulfide lithium greases) with different NLGL (National Lubricant Grease Institute of America) numbers were investigated using terahertz time-domain spectroscopy. Greases with different NLGL grades have unique spectral features in the terahertz range. Comparison of the experimental data with predictions based on Lorentz--Lorenz theory exhibited that the refractive indices of each kind of lubricating grease were dependent on the their consistency. In addition, molybdenum disulfide (MoS2) as a libricant additive shows strong absorption from 0.2 to 1.4 THz, leading to higher absorption of MoS2-lithium grease than that of lithium grease. 相似文献
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We investigate the photovoltaic effects of quartz single crystals annealed at high temperatures in ambient atmosphere. The open-circuit photovoltages and surface morphologies strongly depend on the heating treatments. When the annealing temperature increases from room temperature to 900℃, the rms roughness of quartz single crystal wafers increases from 0.207 to 1.011 nm. In addition, the photovoltages decrease from 1.994μV at room temperature to 1.551 μV after treated at 500℃, and then increase up to 9.8μV after annealed at 900℃. The inner mechanism of the present photovoltaic response and surface morphologies is discussed. 相似文献
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Fast photoelectric effects have been observed in MgB2 thin film
fabricated by chemical vapour deposition. The rise time was $\sim $10
ns and the full width at half-maximum was \sim185\,ns for the photovoltaic
pulse when the film was irradiated by a 308\,nm laser pulse of 25\,ns in
duration. X-ray diffraction and the scanning electron microscope revealed
that the film was polycrystalline with preferred c-axis orientation. We
propose that nonequilibrium electron--hole pairs are excited in the grains
and grain boundary regions for MgB2 film under ultraviolet laser and
then the built-in electric field near the grain boundaries separates
carriers, which lead to the appearance of an instant photovoltage. 相似文献