Papers by Keyword: Verdet Constant

Abstract: Many natural materials have the ability to rotate the polarization level of linearly polarized laser beam and pass through it. This phenomenon is called optical activity. In the event that a light beam (linearly polarized) passes through an optically active material, such as a quartz crystal, and projected vertically on the optical axis, the output beam will be polarized equatorially, and the vibration level will rotate at a certain angle [1], [2], [3]. A number of crystals, liquids, solutions, and vapors rotate the electric field of linearly polarized light that passes through them [4], [5], [6], [7]. Many different physical effects are applied to optical isotropic and transparent materials that cause them to behave as optical active materials, where they are able to rotate the polarization level of the polarized light linearly and pass through it [8], [9], [10]. These effects include mechanical strength, electric field, and magnetic field. By placing one of these effects on an optically transparent medium, it changes the behavior of the light travelling through it [11].

Abstract: Magnetizations and optical Faraday effects have been intensitvely studied in transparent glasses of almost all Lanthanide elements with 20mol % in pulsed magnetic fields up to 30T in the temperature range between 1.8K-RT. The internal effective fields were investigated by observing Verdet constants as a function of applied fields and as a function of magnetizations in the wavelength range between 400nm and 2600nm, intensively for Nd, Pr , Tb and Dy glasses respectively. We obtained a magnet of Dy (30mol%) glass with optically transparent and adhesive to conventional magnet at the room temperature. The magnetizations of these glasses showed paramagnetism at the room temerature and showed super-paramagnetim at cryogenic temperatures below 4.2K.

Abstract: The design and measurement of Verdet constant of magneto optical fiber is reported. An optical beam was found that it linearly polarized at the fiber input changes to elliptically polarized after propagating down the fiber and an elliptical fitting method was studied and reported. Traditional method is based on circle polarized principle, rotation angle is obtained through manually adjust the polarizer which is rather inaccurate especially for small rotations. Through the development of elliptical fitting equations and the test of intensity on major and minor points, fiber Verdet constant can be measured more precisely. The measured data of TZN (TeO₂- ZnO-Na₂CO₃) fiber was verified and it provides improved accuracy compared with existing methods.

Abstract: The measurement of linearly polarized light rotation is the key technique in atomic magnetometer. It influences the sensitivity of atomic magnetometer directly. The basic principle of polarizer beam splitter detecting was analyzed. The ZF7 optical glass and solenoid were used to generate standard small angle based on Faraday effect. The signal of AC rotational angle was extracted by lock-in amplifier. The experiment proved that the method can measure 8×10^-7rad small optical rotation. As the linearly polarized light rotation is 20mrad in atomic magnetometer, the signal to noise ratio reaches 25000.

Abstract: An optical-electronic system for Faraday rotation measurement is designed and constructed to evaluate the verdet constant of magnetic -optical glasses. The works include the optical bench setup and development of software. PbO-Bi2O3-B2O3 glasses systems were fabricated and characterized by using the self-constructed optical bench and the obtained Verdet constants @632.8nm for glass PBB1 was verified by using a commercial powermeter (as detector). The developed measurement system showed characteristics of low cost, small size and accurate.

Abstract: The Verdet constant is the essential parameter of Faraday Effect. Study on Verdet constant of magnetic optical medium is very important in Faraday Effect research and application. In this paper, Verdet constant of liquid and solid medium were investigated with light extinction method with the help of photoelectric detector. Using the square wave magneto-optic modulation method which we established, Verdet constant of air was measured. Variation of Verdet constant of these materials with changes of light wavelength and temperature was investigated. These experimental data may provide reference for research and application of magneto-optic effect. Meanwhile, the experiment in this paper is also one of the key works of magnetic rotation imaging method for geomagnetic field measurement which we proposed. It will provide experimental support for this new geomagnetic field measurement method.

Abstract: The calcium terbium aluminate (CaTbAlO4) single crystal was grown by Czochralski method successfully for the first time.The structure of the crystal was determined by X-ray diffraction analysis.The transmission spectrum of the crystal was measured at room temperature at the wavelength of 400-1500nm.The specific Faraday rotation of the single crystal was surveyed at room temperature at the wavelength 532nm, 633nm, and 1064nm respectively.The Verdet constants of the CaTbAlO4 crystal are calculated and the results show that the Verdet constants of CaTbAlO4 are around 110% higher than that of TGG in the visible and near-infrared spectral region.Therefore,crystal CaTbAlO4 can be promising material for the fabrication of magneto-optical devices in the visible region.

Abstract: . Fe3O4 nanoparticles were synthesized and doped into two glass systems (Na2O-B2O3 glass and PbO-Bi2O3-B2O3-GeO2 glasses) at low concentrations using traditional glass melting method. The formation of Fe3O4 nanoparticles was obtained through coprecipitation of Fe(II) and Fe(III) in alkaline media.The size of the Fe3O4 nanoparticles was observed to be around 15 nm. The structure and properties of doped glasses were studied by X-ray diffraction (XRD), scanning electric microscope (SEM), UV-VIS spectray, FT-IR spectray analysis and Faraday rotation test. Compared to the host glass, Fe3O4 nanoparticles doped glasses shown enhanced Faraday Effect in term of Verdet constant and will have potential application in magneto-optical devices.

Abstract: Fe3O4 nanoparticles doped magnetic-optical PbO-Bi2O3-B2O3 glasses were prepared and studied and the effects of Fe3O4 nanoparticle on the properties of magnetic-optical glass were analyzed. It is found that the doping of Fe3O4 nanoparticles into glasses increased the Verdet constant of magneto optical glass without evident degradation in glass transmittance. The formation of Fe3O4 nanoparticles was obtained through coprecipitation of Fe(II) and Fe(III) in alkaline media. The structure and properties of doped glasses were studied by X-ray diffraction (XRD), scanning electric microscope (SEM), UV-VIS spectray analysis and Faraday rotation test etc.