An aluminum(Al)based nearly guided-wave surface plasmon resonance(NGWSPR)sensor is investigated in the far-ultraviolet(FUV)region.By simultaneously optimizing the thickness of Al and dielectric films,the sensitivity o...An aluminum(Al)based nearly guided-wave surface plasmon resonance(NGWSPR)sensor is investigated in the far-ultraviolet(FUV)region.By simultaneously optimizing the thickness of Al and dielectric films,the sensitivity of the optimized Al-based FUV-NGWSPR sensor increases from 183/RIU to 309/RIU,and its figure of merit rises from 26.47 RIU^(-1)to 32.59 RIU^(-1)when the refractive index of dielectric increases from 2 to 5.Compared with a traditional FUV-SPR sensor without dielectric,the optimized FUV-NGWSPR sensor can realize simultaneous improvement of sensitivity and figure of merit.In addition,the FUV-NGWSPR sensor with realistic materials(diamond,Ta_(2)O_(5),and GaN)is also investigated,and 137.84%,52.70%,and 41.89%sensitivity improvements are achieved respectively.This work proposes a method for performance improvement of FUV-SPR sensors by exciting nearly guided-wave,and could be helpful for the high-performance SPR sensor in the short-wavelength region.展开更多
We demonstrate here that global-scale determination of a key ionospheric parameter,the peak height of the F_(2)region(h_(m)F_(2)),can be obtained by making a simple ratio measurement of the atomic oxygen 130.4 and 135...We demonstrate here that global-scale determination of a key ionospheric parameter,the peak height of the F_(2)region(h_(m)F_(2)),can be obtained by making a simple ratio measurement of the atomic oxygen 130.4 and 135.6 nm emissions in the far-ultraviolet nightglow with a nadir-viewing system such as a pair of photometers suitable for flight on a CubeSat.We further demonstrate that measurements from an altitude that is within the typical range of nighttime h_(m)F_(2)250−450 km can provide the ratios that are needed for retrieval of the h_(m)F_(2).Our study is conducted mostly through numerical simulations by using radiative transfer models of the two emissions coupled with empirical models of the atmosphere and ionosphere.Modeling results show that the relationship between the h_(m)F_(2)and the intensity ratio is sensitive to the altitude from which the emissions are observed,primarily because of the distinctly different degrees of resonant scattering of the two emissions in the atmosphere.A roughly quadratic relationship can be established for observations from an orbit of~400 km,which enables h_(m)F_(2)retrieval.Parametric analysis indicates that the relationship can be affected by the ambient atmospheric conditions through resonant scattering and O2 absorption.For typical nighttime conditions with h_(m)F_(2)250−450 km,retrieval of the h_(m)F_(2)from synthetic observations shows that the typical errors are only a few kilometers(up to~20 km),depending on the accuracy of the ambient conditions predicted by the empirical models.Our findings pave the way for use of the 130.4/135.6 nm intensity ratios for global-scale monitoring of the nighttime ionosphere at mid to low latitudes.展开更多
基金Project supported by the National Natural Science Foundation of China(Grant Nos.61805007 and 11547241)
文摘An aluminum(Al)based nearly guided-wave surface plasmon resonance(NGWSPR)sensor is investigated in the far-ultraviolet(FUV)region.By simultaneously optimizing the thickness of Al and dielectric films,the sensitivity of the optimized Al-based FUV-NGWSPR sensor increases from 183/RIU to 309/RIU,and its figure of merit rises from 26.47 RIU^(-1)to 32.59 RIU^(-1)when the refractive index of dielectric increases from 2 to 5.Compared with a traditional FUV-SPR sensor without dielectric,the optimized FUV-NGWSPR sensor can realize simultaneous improvement of sensitivity and figure of merit.In addition,the FUV-NGWSPR sensor with realistic materials(diamond,Ta_(2)O_(5),and GaN)is also investigated,and 137.84%,52.70%,and 41.89%sensitivity improvements are achieved respectively.This work proposes a method for performance improvement of FUV-SPR sensors by exciting nearly guided-wave,and could be helpful for the high-performance SPR sensor in the short-wavelength region.
基金the National Natural Science Foundation of China through Grant 8206100245the Chinese Meteorological Administration through Grant FY-APP-ZX-2022.0222.
文摘We demonstrate here that global-scale determination of a key ionospheric parameter,the peak height of the F_(2)region(h_(m)F_(2)),can be obtained by making a simple ratio measurement of the atomic oxygen 130.4 and 135.6 nm emissions in the far-ultraviolet nightglow with a nadir-viewing system such as a pair of photometers suitable for flight on a CubeSat.We further demonstrate that measurements from an altitude that is within the typical range of nighttime h_(m)F_(2)250−450 km can provide the ratios that are needed for retrieval of the h_(m)F_(2).Our study is conducted mostly through numerical simulations by using radiative transfer models of the two emissions coupled with empirical models of the atmosphere and ionosphere.Modeling results show that the relationship between the h_(m)F_(2)and the intensity ratio is sensitive to the altitude from which the emissions are observed,primarily because of the distinctly different degrees of resonant scattering of the two emissions in the atmosphere.A roughly quadratic relationship can be established for observations from an orbit of~400 km,which enables h_(m)F_(2)retrieval.Parametric analysis indicates that the relationship can be affected by the ambient atmospheric conditions through resonant scattering and O2 absorption.For typical nighttime conditions with h_(m)F_(2)250−450 km,retrieval of the h_(m)F_(2)from synthetic observations shows that the typical errors are only a few kilometers(up to~20 km),depending on the accuracy of the ambient conditions predicted by the empirical models.Our findings pave the way for use of the 130.4/135.6 nm intensity ratios for global-scale monitoring of the nighttime ionosphere at mid to low latitudes.
