“…Faraday rotation is the rotation of the sense of polarization as an electromagnetic wave passes through a magnetic field in a transparent dielectric [14][15][16][17][18][19].When propagating through the ionosphere, a linearly polarized wave will suffer a gradual rotation of its plane of polarization due to the presence of the geomagnetic field and the anisotropy of the plasma medium [20][21][22][23]. The Faraday rotation Ω can be calculated as follows [21]:…”
This research aims to analyze the impact of the Earth-Space link on the Automatic Identification System (AIS) signals of ships. To achieve this, we established a simulation system that measures the receiving power of AIS signals via satellite platforms. We validated the system by utilizing observation data from Tiantuo-5. Through this simulation, we quantitatively analyzed the effects of ionospheric TEC (Total Electron Content) and space loss on the received power. During the processing of observation data, we construct a geometric propagation model utilizing the measured positions of both the satellite and the ship. We then calculate the antenna gain and remove any system errors. Additionally, we eliminate the deviation of elevation and azimuth angles caused by satellite motion. This allows us to determine the actual power of different ships reaching the receiving platform. Upon comparing the measured power data with the simulated power, it was noted that both exhibited an increasing trend as the elevation angle increased. This led to an RMSE (Root Mean Square Error) result of approximately one, indicating the accuracy of the simulation system. These findings hold significant implications for analyzing interference factors in satellite-ground links.
“…Faraday rotation is the rotation of the sense of polarization as an electromagnetic wave passes through a magnetic field in a transparent dielectric [14][15][16][17][18][19].When propagating through the ionosphere, a linearly polarized wave will suffer a gradual rotation of its plane of polarization due to the presence of the geomagnetic field and the anisotropy of the plasma medium [20][21][22][23]. The Faraday rotation Ω can be calculated as follows [21]:…”
This research aims to analyze the impact of the Earth-Space link on the Automatic Identification System (AIS) signals of ships. To achieve this, we established a simulation system that measures the receiving power of AIS signals via satellite platforms. We validated the system by utilizing observation data from Tiantuo-5. Through this simulation, we quantitatively analyzed the effects of ionospheric TEC (Total Electron Content) and space loss on the received power. During the processing of observation data, we construct a geometric propagation model utilizing the measured positions of both the satellite and the ship. We then calculate the antenna gain and remove any system errors. Additionally, we eliminate the deviation of elevation and azimuth angles caused by satellite motion. This allows us to determine the actual power of different ships reaching the receiving platform. Upon comparing the measured power data with the simulated power, it was noted that both exhibited an increasing trend as the elevation angle increased. This led to an RMSE (Root Mean Square Error) result of approximately one, indicating the accuracy of the simulation system. These findings hold significant implications for analyzing interference factors in satellite-ground links.
“…Diamagnetic materials are typically less temperature dependent than paramagnetic or ferromagnetic materials [35] which often makes them more desirable for sensor applications. A compensation mechanism for reducing the temperature dependence in diamagnetic materials through use of input polarization control has also been developed [55].…”
Section: Sensor Sensitivitymentioning
confidence: 99%
“…These include solid dielectric coaxial transmission line structures, combination travelling wave/noncentered (or noncircular) fiber coil sensors, helical waveguide sensors using higher sensitivity materials, bulk-optic helical-conductor travelling wave sensors, and a serpentine, planar waveguide in an RF stripline. Finally, Chapter 13 summarizes the high frequency response model predictions and experimental measurements for all planar and travelling wave fiber current sensors.CHAPTER EFFECT CURRENT SENSORSThe Faraday effect is an induced circular birefringence created by a magnetic field interacting with an optical medium[35]. The resulting rotation of the plane of polarization, 0, of light propagating in a medium of length L is described (in MKS units)…”
This study investigates the high frequency response of Faraday effect optical fiber current sensors that are bandwidth-limited by the transit time of the light in the fiber. Mathematical models were developed for several configurations of planar (collocated turns) and travelling wave (helical turns) singlemode fiber sensor coils, and experimental measurements verified the model predictions. High frequency operation above 500 MHz, with good sensitivity, was demonstrated for several current sensors; this frequency region was not previously considered accessible by fiber devices. Planar fiber coils in three configurations were investigated: circular cross section with the conductor centered coaxially; circular cross section with the conductor noncentered; and noncircular cross section with arbitrary location of the conductor. Centered, circular coil sensors have a frequency response easily characterized by light transit time. In this category, a 20-turn, 6.4mm diameter annealed fiber sensor was tested up to 1 GHz. It has a 3dB bandwidth of approximately 230 MHz and a sensitivity-bandwidth product of approximately 0.8 MHz-°/A. Both noncentered coils and noncircular coils exhibit a resonant response at the higher frequencies that mimics the response of tapped, recirculating fiber delay lines. Coils with large eccentricity in the cross section feature the same sensitivity in the resonance bands as they do at low frequencies. This frequency response was successfully modeled using a point interaction between the magnetic field and the light in the fiber. The helical travelling wave fiber coils were immersed in the dielectric of a coaxial transmission line to improve velocity phase matching between the field and light. Three liquids (propanol, methanol, and water) and air were used as transmission line dielectrics. Complete models, which must account for liquid dispersion and waveguide dispersion from the multilayer dielectric in the transmission line, were developed to describe the Faraday response of the travelling wave sensors. Large enhancements in current sensor bandwidth are possible without a loss in system sensitivity. A maximum bandwidth of approximately 300 MHz was achieved in a water-dielectric sensor cell containing a 14-turn coil with a 3 cm diameter and a 3 cm helical pitch. This sensor has a sensitivity-bandwidth product of approximately 1.08 MHz-°/A. Other travelling wave current sensors with potentially greater Faraday sensitivity, wider bandwidth and smaller size are investigated using the theoretical models developed for the singlemode fiber coils.
“…The Faraday effect is crucial for numerous scientific and technological advancements in astronomy, biology, chemistry, physics, and materials science. For instance, it is used for investigating the magnetic domain structure in solids 1 , 2 , nuclear magnetic resonance in fluids via optical detection 3 , 4 , paramagnetic gas molecule detection 5 , determination of magnetic fields 6 and electron-density distribution in outer space and celestial objects 7 , probing spin coherence in cold atoms 8 , quantum spin fluctuation measurements 9 , biochemical and biomolecular detection 10 , stabilization of laser frequency 11 , optical current sensing 12 , optical Hall effect 13 , and optical isolators 14 .…”
Section: Introductionmentioning
confidence: 99%
“…While Faraday rotation is generally accompanied with ellipticity when light passes through an absorbing medium (Fig. 1 ), a measurement of only Faraday rotation is sufficient for obtaining all the magneto-optical information about the sample 1 . Fig.…”
Faraday rotation is a fundamental effect in the magneto-optical response of solids, liquids and gases. Materials with a large Verdet constant find applications in optical modulators, sensors and non-reciprocal devices, such as optical isolators. Here, we demonstrate that the plane of polarization of light exhibits a giant Faraday rotation of several degrees around the A exciton transition in hBN-encapsulated monolayers of WSe2 and MoSe2 under moderate magnetic fields. This results in the highest known Verdet constant of -1.9 × 107 deg T−1 cm−1 for any material in the visible regime. Additionally, interlayer excitons in hBN-encapsulated bilayer MoS2 exhibit a large Verdet constant (VIL ≈ +2 × 105 deg T−1 cm−2) of opposite sign compared to A excitons in monolayers. The giant Faraday rotation is due to the giant oscillator strength and high g-factor of the excitons in atomically thin semiconducting transition metal dichalcogenides. We deduce the complete in-plane complex dielectric tensor of hBN-encapsulated WSe2 and MoSe2 monolayers, which is vital for the prediction of Kerr, Faraday and magneto-circular dichroism spectra of 2D heterostructures. Our results pose a crucial advance in the potential usage of two-dimensional materials in ultrathin optical polarization devices.
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