Verdet Constant Measurement Research Articles

Temperature Correlation Effect of Transverse Magneto-Optic Error in Miniaturized Fiber Optic Gyroscope

A temperature correlation effect of transverse magneto-optic error in miniaturized fiber optic gyroscopes is proposed. The theoretical model based on mode perturbation and temperature correlation terms is established. The temperature dependence of the Verdet constant is measured by the thermo-controlled Verdet constant measurement system based on the phase-sensitive detection. And the temperature dependence of the refractive index is analyzed by the multi-physics finite element method. The experiment based on the miniaturized FOG prototype with two kinds of fibers is carried out. Experimental result shows that the average temperature correlation coefficients of TMOE with polarization-maintaining fibers and photonic-crystal fibers are 5.335×10 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">-4</sup> °/h/Gs/°C and 2.377×10 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">-4</sup> °/h/Gs/°C, which are in good agreement with the analysis results.

Thermal, nonlinear, magnetic and faraday rotation properties of sol-gel diamagnetic glass /NaYF4: Fe, Ho3+: Role of magnetic ions

Ho3+ owns the biggest magnetic moment, stark splitting of energy and low-symmetry D2 crystal field which make Ho3+ high polarizable and has been studied as dopant in several magnetic crystals. For the first time, Ho3+ doped sol-gel synthesized diamagnetic glass for nonlinear, magnetic and magneto optical study was reported. This paper reports the synthesis, structure, morphology and magnetization of hexagonal NaYF4:Fe, Ho nanorods and importantly, the influence of NaYF4:Fe, Ho to the thermal, nonlinear, magnetic and Faraday rotation of diamagnetic glasses through varies techniques such as X-ray diffraction, scanning electron microscopy, Raman spectra, Ultraviolet–visible spectra, different scanning calorimetry, thermal mechanical analysis, Z-scan, superconducting quantum interference device magnetometry and Verdet constant measurement. Experimental results discovered that the doping of Ho3+ and Fe3+ ions disturbed the self-assembly of NaYF4 while suppressed the length of nanorod. Due to its nanoscale, magnetization of NaYF4:Fe, Ho changed from diamagnetic to superparamagnetic. The doping of NaYF4:Fe, Ho increased the thermal stability and third nonlinearity. Glass with different amount of doping presented diamagnetism and paramagnetism due to the strongest magnetic moment, increased polarizability, electron transition of Ho3+ and d-d exchange of Fe3+ ions in glass matrix. Glass doped 2% of NaYF4:Fe, Ho glass showed the best magnetic, magneto optical performance and improved thermal stability and nonlinearity which can be ideal candidate for photonics, nonlinear and magneto optical applications.

Bi1.9Mn0.1Te3 nanocrystal functionalized diamagnetic glasses: optical, luminescence, magnetic and Faraday rotation

Mn doped Bi2Te3 nanocrystal, both as topological insulator and diluted magnetic semiconductor, has gained significant interest due to its interesting magnetic performance roused by the sp-d exchange interaction and unique time-reversal symmetry protected surface states. In this paper, for the first time, Bi1.9Mn0.1Te3 nanocrystal doped diamagnetic TeO2–PbO–B2O3 glass was studied. Pure 50nm hexagonal Bi1.9Mn0.1Te3 nanocrystals were synthesized with a specific surface area of 64.28 m2/g using the optimized PEG as surfactant. Due to the complex spin-orbit interactions between sp band of Bi2Te3 and d band of Mn, the prepared Bi1.9Mn0.1Te3 displayed characteristic luminescence, A11g, E2g, A21g Raman modes, good photocatalytic (70.2%) and ferromagnetic/paramagnetic co-existence behavior.Bi1.9Mn0.1Te3 doped diamagnetic glasses were prepared by melting-quenching technique and the influence of different doping amount to glass structure and properties was evaluated through X-ray diffraction, Fourier transforms infrared, Raman, Ultraviolet-visible, photoluminescence spectra and Verdet constant measurement. The glasses structure and properties were doping amount dependent. X-ray diffraction, Fourier transforms infrared and Raman spectra revealed the evolution of structure units of TeO4, TeO3, BO3 etc under the modification of Bi1.9Mn0.1Te3. SEM revealed the homogeneity and growth of nanocrystals in matrix. X-ray photoelectron spectroscopy displayed the chemical states changes of Mn2p, Bi4f, Te3d and O1s under different doping amounts. Both the optical absorption band at 540nm and cutoff wavelength increased with the dopant amount. The luminescence in visible range revealed the tetrahedral coordination state of paramagnetic Mn ions which also influenced the magnetization and Faraday rotation accordingly. Experimental results showed that glass with 2%Bi1.9Mn0.1Te3 exhibited good optical, luminescence, magnetic, significant high Verdet constant (0.2522min/G.cm) and good thermal stability as well. Such good quality diamagnetic glass is attractive for magneto-optical devices applications in isolator and current transducer etc.

Fluorophosphate Glasses with High Terbium Content for Magneto-optical Applications

Fluorophosphate glasses are investigated following the composition law (1 – x)(70NaPO3 – 30BaF2) – xTbF3 with x = 35, 40, 45, and 50 mol %. Bubble-free vitreous rods of 5 cm length and 4 mm in diameter are obtained without crystallization from 35 to 50 mol % of TbF3 by using the conventional melt-quenching process. The maximum content of Tb3+ ions successfully dissolved in these glasses corresponds to an ionic density of 8.88 × 1021 ions cm–3, which is the highest value ever reported in a fluorophosphate glass matrix, to our knowledge. Thermal, structural, and optical properties were characterized respectively by DSC, Raman spectroscopy, prism coupling technique, UV–visible-NIR, and Verdet constant measurement. The increase of the terbium content from 35 to 50 mol % in the glass results in an increase of its glass transition temperature (Tg) from 352 to 390 °C, a decrease of its thermal stability against crystallization (ΔT) from 153 to 73 °C, and an increase of both its refractive index and Verdet consta...

The structure, spectra and properties of Dy2O3 modified diamagentic lead-bismuth-germanium glasses

Dy2O3 is potential and attractive as scintillator, mid infrared laser and Faraday rotation materials in high energy physics, general radiation and magneto optical sensing systems. In this study, Dy3+ doped diamagnetic glasses with compositions of 10GeO2 – 30PbO – 50Bi2O3 – (10-x)B2O3 –xDy2O3 (x = 0, 0.5, 1, 2, 3, 5 M %) were fabricated by a melt quenching technique. The modification of Dy3+on glass forming, structure, UV–Vis, FT-IR, Raman and photoluminescence spectra and properties were investigated through XRD, Raman spectra, DSC, Vicker's hardness and Verdet constant measurements etc. Melt with Dy2O3 content beyond 5% prefer to crystallize, not to form glassy matrix. The UV visible absorption spectra showed three intense bands at 483 nm, 575 nm and 661 nm due to 4F9/2 → 6H15/2 (blue), 4F9/2 → 6H13/2 (yellow) and 4F9/2 → 6H11/2 (red) transitions, respectively. Judd-Ofelt paramaters have been calculated to verify network connectivity of Dy2O3 doped glasses. FT-IR and Raman spectrum depicted the presence of PbO4, BiO3, GeO6, BO3 frame groups and DyO bonds from cubit Dy2O3. Glass doped with 1%Dy2O3 exhibited promising thermal stability (97 °C), microhardness (480 HV) and magneto-optical activity (0.1864 min/G.cm@532 nm) due to the high optical dispersion, high ion polarizability of Dy3+ ions

Multiferroic BiFeO3 enhanced Faraday rotation effect in magneto optical glasses

Single phase multiferroic BiFeO3 nanocrystals and BiFeO3 doped magneto optical BiFeO3–PbO–Bi2O3–B2O3 glasses have been synthesized and characterized in this study. Through the X-ray diffraction, Scanning electron microscopy, differential scanning calorimetry, UV–Vis optical absorption, Vicker's hardness and Verdet constant measurement, the glass structure and spectral were found to be modified by BiFeO3 nanocrystal, and Faraday rotation, absorption edge and mechanical performance of glasses were improved by such modification due to the low band gap, high polarization, ferromagnetic & superparamagnetic property of nanocrystal BiFeO3. Glass of 5%BiFeO3–40%PbO–50%Bi2O3–5%B2O3 exhibits a Verdet constant of 0.1615 min/G·cm at 633 nm, thermal stability of 105 °C and a 510 nm cutoff wavelength which is very attractive to magneto optical glass devices.

Structure, spectra and thermal, mechanical, Faraday rotation properties of novel diamagnetic SeO2-PbO-Bi2O3-B2O3 glasses

Faraday rotation diamagnetic glass has attracted research attentions in photonics, sensing and magneto optical devices due to their high refractive index, wide transmittance in UV and Fourier transform infrared (FT-IR) range and temperature independent Faraday rotation. Selenite modified heavy metal oxides glasses with composition of xSeO2-(10-x) B2O3-45PbO-45Bi2O3 (x = 0, 1, 5 and 10mol%) and 15%SeO2-40%PbO-45%Bi2O3 have been fabricated by melt-quenching method in present study. The influence of SeO2 on glass forming ability, thermal, mechanical properties and Faraday rotation were evaluated through X-ray Diffraction (XRD), Fourier transforms infrared spectra (FT-IR), Raman, X-ray photoelectron spectroscopy (XPS), differential scanning calorimetry (DSC), Vicker's hardness and Verdet constant measurements. XRD spectra reveal that the good vitrification was achieved for glass with SeO2 amounts ≤10% even without B2O3. FT-IR, Raman and XPS spectra ascertain the existence of characteristic vibration of SeO4, SeO3, PbO4, BiO3 and BO3 units. The incorporation of SeO2 increases the connectivity of glassy network by increasing the Tg, thermal stability and mechanical hardness. The small band gap, high polarizable Se4+ ions and isolated SeO3 units contribute to Faraday rotation improvement.

SnO2 modified thermal, mechanical and magneto optical property improvement of PbO-Bi2O3-B2O3 glass

SnO2 is a widely accepted room temperature ferromagnetic material and has found applications in rapidly growing fields of spintronics and magneto electronics. Faraday rotation diamagnetic glass has attracted research attentions in photonics, sensing and magneto optical devices due to their high refractive index, wide transmittance in UV and Fourier transform infrared (FT-IR) range and temperature independent Faraday rotation. In this paper, we report for the first time the fabrication of SnO2 modified diamagnetic glass with composition of xSnO2-(10-x) B2O3-30PbO-60Bi2O3 (x = 0, 2, 4, 6, 8 and 10 mol%) by melt-quenching method. The influence of SnO2 on glass forming ability, thermal, mechanical properties and Faraday rotation were evaluated through X-ray Diffraction (XRD), FT-IR, Raman, X-ray photoelectron spectroscopy (XPS), differential scanning calorimetry (DSC), Vicker's hardness and Verdet constant measurements. Good vitrification was achieved with SnO2 amount ≤ 6 mol%. XRD spectra confirmed that too much SnO2 exist as distorted SnO6 polyhedra and there is obvious direct interaction between tin and Bi2O3 structural units. FT-IR, Raman and XPS spectra ascertain the existence of characteristic vibration of SnO4, SnO6, PbO4, BiO3 and BO3 units. Glass with 4%SnO2 exhibited significant good glass thermal stability (102 °C), big Vicker's hardness (369 HV), high Verdet constant (0.1424 min/G.cm at 633 nm) and big cutoff wavelength (432 nm) due to the enhanced network connectivity, brought about by inclusion of high polarization and magnetization strong Sn–O linkages.

Wavelength dependence of Verdet constant of Pr doped terbium gallium garnet crystal

Samples of the magneto-active material – Pr3+: Tb3Ga5O12 crystals with Pr3+ ion concentration of 1%, 2%, 3% and 5%. The Verdet constant measurement has been carried out at room temperature in the 400–1500 nm range for all crystal samples and was compared with a pure Tb3Ga5O12 material. A high value of the Verdet constant for 5% Pr3+: Tb3Ga5O12 crystal was obtained at room temperature – namely, 324.5, 200.1 and 68.7 rad/(T·m) for 532, 632.8 and 1064 nm, respectively. The Verdet constant of Pr doped TGG crystal at 1064 nm is much more higher than that of TGG. The superior performance of the materials indicates that Pr3+: Tb3Ga5O12 crystals have great potential to meet the increasing demand for magneto-optical devices in the VIS-NIR wavelength.

Verdet constant measurements of β-barium borate and lead molybdate crystals

Verdet constants of beta-barium borate (β-BaB2O4, BBO) and lead molybdate (PbMoO4, PMO) crystals are measured by comparing with that of terbium-doped glass. Measurement uncertainties caused by light intensity fluctuation, responsiveness drift of photo-detector and unstable amplifying ratio of signal processing circuits can be suppressed by comparative measurement method. Verdet constants of the BBO and PMO crystals respectively are 5.61 ± 0.17 rad.T−1.m−1 and 51.7 ± 1.5 rad.T−1.m−1 for light wavelength of 635nm.

Two-Frequency Paired Polarization Interferometer for Faraday Rotation Angle Detection

A highly sensitive two-frequency paired linear polarized interferometer (TPPI) for measuring the Faraday rotation angle and Verdet constant of the Bi12SiO20 (BSO) crystal in real time was set up by an amplitude-sensitive detection method. TPPI features a common-path heterodyne interferometer in conjunction with a highly correlated paired linear polarized laser beam. Then, the antisymmetry of polarized heterodyne signals is produced and Faraday rotation angle detection by a balanced detector scheme is satisfied automatically. As a result, shot-noise-limited detection of Faraday rotation angle is possible. In addition, the Faraday rotation angle detection is also insensitive to the scattering and absorption caused by the specimen because of the common-path propagation of the paired linear polarized laser beam. Experimentally, the sensitivities of Faraday rotation angle and Verdet constant measurements of the BSO crystal under the arrangement with a single pass of the laser beam in TPPI are 4.93×10-5 rad/mm and 2.6×10-7 rad/(mT·mm), respectively. This suggests that the Faraday rotation angle detection sensitivity has the potential to be on the order of 10-8 rad/mm if a Fabry–Perot cavity with a finesse of F=120 is used in TPPI.

High sensitivity two-frequency paired polarized interferometer in Faraday rotation angle measurement of ambient air with single-traveling configuration

High sensitivity detection on Faraday rotation and Verdet constant of ambient air under weak applied magnet field and single-pass configuration specimen is setup in which a two-frequency paired linear polarized interferometer (TPPI) coupled with balanced detector shown at shot-noise-limited detection is demonstrated. The Verdet constant of ambient air at 1.3×10−6 rad/mT m and its sensitivity at 4.3×10−8 rad/mT m were measured. Additionally, this method also is able to extend into a broad spectral range on Faraday rotation angle or Verdet constant measurement. Finally, the enhancement on detection sensitivity by integrating a Fabry–Pérot cavity into TPPI is discussed.

Micro-pulling-down growth and characterization of Tb 3− xTm xAl 5O 12 fiber crystals for Faraday rotator applications

The effect of the thulium (Tm) substitution in the Tb 3Al 5O 12, Tb 3− x Tm x Al 5O 12 (TTAG) mixed garnet crystals, has been studied by the solidification of corresponding stoichiometric melts using a micro-pulling down apparatus. The phase composition for the TTAG crystals with different Tm 3+ concentrations was determined by powder X-ray diffraction analysis. The amount of the TbAlO 3 perovskite phase in the as-grown TTAG fibers was observed to decrease with substitution of Tm 3+ in Tb 3+ site. The lattice parameters of the TTAG were reduced with increase of concentration of Tm 3+. The results of the Verdet constant measurements are also reported.

Terbium gallium garnet Verdet constant measurements with pulsed magnetic field

The dispersion of the Verdet constant of a single-crystal terbium gallium garnet (TGG) was measured using a pulsed magnetic field up to 70 KG. The data show a large Verdet constant for TGG throughout the visible region. The observed hysteresis effect is briefly discussed.

Faraday Rotation in YIG and TbIG

Measurements of the Faraday rotation in YIG and TbIG have been made as a function of temperature in the range 100°–450°K at the helium-neon laser wavelength of 1.15 μ. This wavelength lies on the edge of the YIG window at the short-wavelength absorption limit. Measurements were made on single-crystal blocks of YIG and TbIG up to 7 mm thick in applied fields of up to 10 kOe. In YIG the major contribution to the Faraday rotation at this wavelength is the dispersive part associated with absorption bands in the visible and near ir. This contribution reaches a maximum of 188°/cm at 280°K and can be fitted to the sublattice magnetization data of Anderson. For TbIG we find αF = 448°/cm at 300°K and a very strong temperature dependence. In addition we observe a field-dependent Faraday rotation of −3.8°/cm/kOe at 300°K. Extrapolation of the observed rotations to zero internal field removes he discontinuity in | αF | which otherwise appears at the compensation temperature (245°K). The zero-field Faraday rotation may be analyzed in terms of three contributions: a nondispersive part arising from the exchange resonance, a dispersive part arising from the Fe3+ sublattices, and a dispersive contribution from the Tb3+ sublattice. Additional information on the Tb3+ contribution was obtained from Verdet constant measurements on TbGaG and TbAlG.

The van der Waals interaction of two or three atoms

The van der Waals interaction of neutral atoms may be characterized by two-body constants CAB and three-body constants CABC. A recent analysis of spectroscopic, refractive index and Verdet constant measurements has been combined with a simple technique for evaluating oscillator strength summations to give CAB for all pairs and CABC for all triplets of the atoms H, He, Ne, Ar, Kr and Xe. The results are believed to be accurate to within 10%.