Due to interaction with the vacuum of the radiation field,a K-type atomic system with near-degenerateexcited and ground levels,which is driven by two strong coherent fields and two weak probe fields,has additional coh...Due to interaction with the vacuum of the radiation field,a K-type atomic system with near-degenerateexcited and ground levels,which is driven by two strong coherent fields and two weak probe fields,has additional coherenceterms—the vacuum-induced coherence (VIC) terms.In this paper,we find that,if the interference is optimized,thetwo-photon absorption properties of this atom system can be significantly modified and electromagnetically-inducedtransparency (EIT) is dependent on this interference.Furthermore,we find that in all the cases the coherence can suppressor enhance the partial two-photon transparency,while the complete transparency window is still strictly preserved,whichmeans that it cannot be affected by the VIC.Another important result is the finding of the crucial role played by therelative phase between the probe and coupling fields:the relative height of absorption peaks can be modulated by therelative phase.The physical interpretation of the phenomena has been given.展开更多
Experimental investigations were conducted in this study to explore the effect of magnetization on water sample properties and to envisage whether the effect is beneficial for mercury detection in a sample of water or...Experimental investigations were conducted in this study to explore the effect of magnetization on water sample properties and to envisage whether the effect is beneficial for mercury detection in a sample of water or not. Subjecting the water sample to 0.3 Tesla magnetic field for 14 hours led to instantaneous effects on the examined water properties, where a reduction in the values of pH (7%) and interfacial tension (0.2%) was observed, whereas an increase (8%) in water electrical conductivity was recorded. Similar behaviours with slight changes in trend were observed after storing the samples for six days, which indicates a creation of permanent effects. Other experiments were conducted to explore the impact of magnetizing water sample containing inorganic mercury prior to detection by emission spectroscopy. Samples were prepared with different mercury concentrations and derivatized by using tin chloride (SnCI2). The generated mercury vapour species were transported with aid of carrier gas into a dielectric barrier discharge plasma atomizer, in which the mercury signal at 253.65 nm was recorded. The results have shown 3.5%-7.5% increase in the signal intensities recorded for the magnetized samples, mostly attributed to a reduction in the sample surface tension and other reasons, which facilitates analyte derivatization.展开更多
Air-core photonic bandgap fiber(PBF)is the perfect choice of the next-generation fiber optical gyroscope(FOG),with excellent temperature,electromagnetism and radiation adaptability.Numerical aperture is an important o...Air-core photonic bandgap fiber(PBF)is the perfect choice of the next-generation fiber optical gyroscope(FOG),with excellent temperature,electromagnetism and radiation adaptability.Numerical aperture is an important optical parameter of PBF for application in FOG.The PBF’s maximum theoretical numerical aperture(NAmax)is calculated and compared with the far-field numerical aperture(NAeff)through experiments.The result indicates that the relationship between NAmax and NAeff has much stronger dependence on wavelength than that of the conventional fiber,and they get close at wavelengths near the middle of the photonic bandgap with the error less than 5%.Furthermore,photonic bandgap fiber optical gyroscope(PBFOG)with no fusion splicing points is proposed,and the optimization method and results of the PBF’s structure parameters for application in PBFOG are given from the aspect of numerical aperture.展开更多
基金National Natural Science Foundation of China under Grant Nos.90503088 and 10775100the Fund of Theoretical Nuclear Center of HIRFL of China
文摘Due to interaction with the vacuum of the radiation field,a K-type atomic system with near-degenerateexcited and ground levels,which is driven by two strong coherent fields and two weak probe fields,has additional coherenceterms—the vacuum-induced coherence (VIC) terms.In this paper,we find that,if the interference is optimized,thetwo-photon absorption properties of this atom system can be significantly modified and electromagnetically-inducedtransparency (EIT) is dependent on this interference.Furthermore,we find that in all the cases the coherence can suppressor enhance the partial two-photon transparency,while the complete transparency window is still strictly preserved,whichmeans that it cannot be affected by the VIC.Another important result is the finding of the crucial role played by therelative phase between the probe and coupling fields:the relative height of absorption peaks can be modulated by therelative phase.The physical interpretation of the phenomena has been given.
文摘Experimental investigations were conducted in this study to explore the effect of magnetization on water sample properties and to envisage whether the effect is beneficial for mercury detection in a sample of water or not. Subjecting the water sample to 0.3 Tesla magnetic field for 14 hours led to instantaneous effects on the examined water properties, where a reduction in the values of pH (7%) and interfacial tension (0.2%) was observed, whereas an increase (8%) in water electrical conductivity was recorded. Similar behaviours with slight changes in trend were observed after storing the samples for six days, which indicates a creation of permanent effects. Other experiments were conducted to explore the impact of magnetizing water sample containing inorganic mercury prior to detection by emission spectroscopy. Samples were prepared with different mercury concentrations and derivatized by using tin chloride (SnCI2). The generated mercury vapour species were transported with aid of carrier gas into a dielectric barrier discharge plasma atomizer, in which the mercury signal at 253.65 nm was recorded. The results have shown 3.5%-7.5% increase in the signal intensities recorded for the magnetized samples, mostly attributed to a reduction in the sample surface tension and other reasons, which facilitates analyte derivatization.
基金supported by the National Natural Science Foundation of China(Grant No.61205077)
文摘Air-core photonic bandgap fiber(PBF)is the perfect choice of the next-generation fiber optical gyroscope(FOG),with excellent temperature,electromagnetism and radiation adaptability.Numerical aperture is an important optical parameter of PBF for application in FOG.The PBF’s maximum theoretical numerical aperture(NAmax)is calculated and compared with the far-field numerical aperture(NAeff)through experiments.The result indicates that the relationship between NAmax and NAeff has much stronger dependence on wavelength than that of the conventional fiber,and they get close at wavelengths near the middle of the photonic bandgap with the error less than 5%.Furthermore,photonic bandgap fiber optical gyroscope(PBFOG)with no fusion splicing points is proposed,and the optimization method and results of the PBF’s structure parameters for application in PBFOG are given from the aspect of numerical aperture.