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Optical and magneto-optical properties of Nd0.1La0.1Y1.8O3 transparent ceramics
摘要： Transparent ceramics in the form of yttrium oxide (Y2O3) doped with La and Nd and pure yttrium as a reference material were successfully prepared via modified sol-gel processes and hot isostatic pressure sintering. Their structure and microstructure were examined by means of scanning electron microscopy and X-ray diffraction, which revealed the high density and single-phase character of these materials. Their optical and magneto-optical properties were also analyzed. Emission spectra of Nd0.1La0.1Y1.8O3 after excitation performed with a continuous 808 nm laser beam showed strong and sharp emission lines. The luminescence lifetime was also investigated. The doped material exhibited a high Verdet constant of over 1000 deg/T?m. The figure of merit was calculated in the VIS spectrum. The investigated transparent oxide ceramics can be considered a promising material for application in lasers and magneto-optical devices.
关键词： Y2O3,Verdet constant,Optical properties,Luminescence,Microstructure,Transparent ceramics
更新于2025-09-23 15:22:29
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[IEEE 2019 Conference on Lasers and Electro-Optics Europe & European Quantum Electronics Conference (CLEO/Europe-EQEC) - Munich, Germany (2019.6.23-2019.6.27)] 2019 Conference on Lasers and Electro-Optics Europe & European Quantum Electronics Conference (CLEO/Europe-EQEC) - N-Matrix Jones Analysis of a Fiber-Optic Current Sensor
摘要： Fiber-optic current sensors (FOCS) based on Faraday effect could potentially be exploited in several high voltage applications where the electromagnetic immunity is a mandatory requirement. Nevertheless their actual in-field exploitation has always been limited due to critical issues such as fiber residual birefringence that degrades the current measurement accuracy. To this purpose special low-birefringence fibers and spun fibers featuring minimal residual birefringence have been developed. Yet these solutions do not prevent the birefringence contribution induced by the curvature arising during the realization of the current sensing coil. In the present work a novel numerical simulator based on the N-matrix Jones formalism [1] has been developed to analyse the detrimental effect of the birefringence on the Faraday-induced rotation of the state of polarization (SOP) of the light inside a FOCS due to the presence of an electrical current. In particular, the simulator takes into account both the intrinsic fiber birefringence and the bending-induced birefringence [2], combined with the circular birefringence caused by the Faraday effect. Simulation results have evidenced interesting behaviors related to the dependence of the effective Verdet constant Veff on both the number N of turns of the sensing fiber coil and the coil curvature radius r. Indeed Veff represents the FOCS effectiveness in inducing a polarization rotation theta, which is directly proportional to the electrical current I according to: ? = 2Veff (N ,r) ? N ? I . (1) In particular, simulations have shown that increasing N the values of Veff reduce due to the presence of intrinsic and bending-induced birefringence. This implies that the FOCS effectiveness does not grow linearly with N. A same trend also occurs when the coil radius r is progressively reduced. The simulation results have also been experimentally validated with the polarimetric setup shown in Fig. 1(a). The FOCS has been realized by wrapping a standard single-mode ?bre around an electrical cable supplied with an AC current up to a rms value of 35 A at the frequency of 50 Hz. A linearly polarized laser at 1.55 μm is coupled to the fiber coil through a circulator and reflected back to the receiver by a Faraday rotator mirror (FRM). This FRM cancels out all the reciprocal birefringence effect in the retracing path, while maintaining the Faraday rotation to be measured [3,4]. At the receiver side the orthogonal components of the SOP of the light are analyzed by means of a polarizing-beam splitter (PBS) together with a pair of photodiodes (PD1, PD2) and the Faraday-induced rotation is recovered.
关键词： Fiber-optic current sensors,Faraday effect,N-matrix Jones formalism,Verdet constant,birefringence
更新于2025-09-16 10:30:52
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[IEEE 2019 Conference on Lasers and Electro-Optics Europe & European Quantum Electronics Conference (CLEO/Europe-EQEC) - Munich, Germany (2019.6.23-2019.6.27)] 2019 Conference on Lasers and Electro-Optics Europe & European Quantum Electronics Conference (CLEO/Europe-EQEC) - Characterization of the Verdet Constant of Dy <sub/>2</sub> O <sub/>3</sub> Ceramics in the Two-Micron Spectral Range
摘要： High-power solid-state mid-IR lasers are being actively developed, as they possess the key properties for a vast number of technological applications [1] (e. g. lidar, gas sensing, or pump sources optical parametric oscillators) and are in a high demand for basic research as well [2]. These potentialities have recently led to intensive investigations of new mid-IR laser gain media [3,4] and other optical elements. One of the key components under investigation is an optical isolator (OI), a magneto-optical device enabling safe operation of a laser by preventing harmful back-reflections into the laser cavity. The development of high-power OIs is particularly challenging due to the severe thermal effects which arise because of the relatively high absorption of the currently available magneto-optical elements. Therefore, a lot of scientific effort is being put into the research of novel magneto-optical materials with the desired properties: high Verdet constant, low absorption and excellent thermal properties. All of these properties enable a reduction of the heat generated in the magneto-optical element. A large number of new magneto-optical materials for high-power OIs have been reported in the recent years. The vast majority of these reports targeted materials suitable for the wavelengths around 1 μm (corresponding to the neodymium and ytterbium doped gain media) in the task to find a better alternative to the most commonly used magneto-optical material for this spectral range – the terbium gallium garnet (TGG) [5]. In this manner, materials based on highly magnetically active rare-earth ions (e. g. Ce3+ [6], Tb3+ [7] or Ho3+ [8]) have been established as a possible next generation of magneto-optical materials for the visible and near-IR OIs. Some of these materials possess local transparency windows in the mid-IR as well, however, reports dealing with their magneto-optical characteristics in this region (or reports of any other suitable materials) were so far very rare. Nevertheless, Verdet constants of CeF3 crystal [9], DyxY0.95-xLa0.05O3 ceramics (with variable doping X = 0.7 – 0.9) [10] and EuF2 crystal [11] have been recently reported at the wavelength of ~1.94 μm, having ~7, ~10 - 14, and ~12 rad/Tm respectfully. We present broadband experimental characterizations of the Verdet constant of three novel material samples of Dy2O3-based ceramics in a broad spectral range 0.6 – 2.4 μm with the relative error of the measurement ~5%. An analytical approximation of the data is a challenging task due to the multiple resonances and absorption bands of Dy3+ ions within the measured range and is currently under investigation. The obtained values for the Verdet constant at 1.94 μm were 17.8, 22.2 and 26.8 rad/Tm predicting a high potential for Dy2O3 ceramics utilization in a high-power mid-IR OIs. The measured transmittances of our samples at 1.94 μm were equal to 54%, 72% and 76%.
关键词： mid-IR lasers,optical isolators,magneto-optical materials,Dy2O3 ceramics,Verdet constant
更新于2025-09-12 10:27:22
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Room‐Temperature Self‐Assembled Preparation of Porous ZnFe <sub/>2</sub> O <sub/>4</sub> /MIL‐100(Fe) Nanocomposites and Their Visible‐Light Derived Photocatalytic Properties
摘要： The long-term temperature induced errors caused by fiber λ/4 wave plate and the Verdet constant of sensing fiber in the all fiber current transformer (FOCT) are theoretically analyzed. A temperature related response of fiber λ/4 wave plate is adopted to compensate for the change caused by temperature related Verdet constant through choosing appropriate initial phase retardation of the λ/4 wave plate. The experimental results show high temperature-cycle accuracy in this kind of FOCT with relative error within 0.6%.
关键词： temperature induced error,λ/4 wave plate,phase delay,Verdet constant,all fiber current transformer
更新于2025-09-11 14:15:04
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[IEEE 2019 Conference on Lasers and Electro-Optics Europe & European Quantum Electronics Conference (CLEO/Europe-EQEC) - Munich, Germany (2019.6.23-2019.6.27)] 2019 Conference on Lasers and Electro-Optics Europe & European Quantum Electronics Conference (CLEO/Europe-EQEC) - Near-Infrared Wavelength Dependence of Verdet Constant in Tb <sub/>2</sub> Zr <sub/>2</sub> O <sub/>7</sub> Transparent Ceramics
摘要： Transparent ceramics are widely developing for optical windows, laser gain mediums, phosphors for the LED lighting, and magneto-optic (MO) applications. In particular, advantages from the glass material or the single crystal of MO ceramics are notable for the high-power lasers from the view point of the large size capability, good thermal properties, and superior magneto-optics properties. Now a day, ceramic technology can realize several kind of cubic oxide materials such as terbium gallium garnet (TGG) [1-4], terbium aluminium garnet (TAG) [5], and sesquioxides [6-8]. In addition of above materials, Tb2Zr2O7 (TZO) transparent ceramics is a new candidate material for the high-power laser application. TZO has a relatively high concentration of Tb3+ ion, a cubic pyrochlore structure, and no intrinsic absorption in the near infrared (NIR) region. To evaluate the potential of this material for the high-power laser application, we have evaluated the near-infrared (NIR) wavelength dependence of Verdet constant in TZO ceramics as the first time.
关键词： magneto-optic applications,transparent ceramics,Tb2Zr2O7,near-infrared,Verdet constant
更新于2025-09-11 14:15:04