Faraday effect measurements of holmium oxide (Ho₂O₃) ceramics-based magneto-optical materials

Abstract

Faraday effect measurements of holmium oxide (Ho 2 O 3 ) ceramics-based magneto-optical materials, highly potential material candidates for high-energy laser Faraday isolators, are presented in this paper. Temperature dependence of the Verdet constant of nondoped Ho 2 O 3 ceramics was measured for temperatures 15-305 K at 1.064 µm wavelength. The Verdet constant dispersion for wavelengths 0.5-1 µm and 1.064 µm was measured for both nondoped Ho 2 O 3 ceramics and Ho 2 O 3 ceramics doped with terbium Tb 3+ (0.2 at. %) and cerium Ce 3+ (0.1 at. %) ions. The results suggest that the relatively low level of doping of Ho 2 O 3 with these ions has no significant boosting impact on the Faraday effect. Therefore, other compositions of Ho 2 O 3 ceramics-based magneto-optical materials, as well as various doping concentrations, should be further examined.

Fabrication and Magneto-Optical Properties of Yb2O3 Based Ceramics

“…The results of measuring the Verdet constant for 4% La:Yb 2 O 3 ceramics are shown in Figure 7 in comparison with the widely used TGG material (see Figure 7a) and with some other known magneto-optical materials which are transparent in the spectral range beyond 1.4 µm (see Figure 7b). The dependences of the Verdet constant on the wavelength are obtained by approximating experimental data for a TGG single crystal [32], Dy 2 O 3 ceramics [20] using the approximation formula from [33], Er 2 O 3 ceramics [25], Ho 2 O 3 ceramics [24,35], EuF 2 , NHF single crystals [36], and for some types of magneto-optical glasses: ternary phosphate glass [37] and TeO 2 [38]. and this dependence is very different in the region of absorption bands (0.9-1.1 µm), where it is impossible to use this material as a magneto-optical one.…”

Verdet Constant of Magneto-Active Materials Developed for High-Power Faraday Devices

“…This review presents the characterization method based upon a modified version of the polarization-stepping technique [44], which has been systematically developed in the recent years [45][46][47][48]. One of the main advantages of this method is that the rotation angle induced in the examined material sample is analyzed based on a large number of angular positions (typically a few hundred) of the analyzing polarization-sensitive element of the experimental detection system.…”

“…This configuration was used in the investigations in Refs. [45][46][47], and its main advantage is the relative simplicity of the setup, compared with the other configurations. Furthermore, assuming we measure the Verdet constant on a single wavelength only (we use a laser probe beam except the broadband source), the spectrometers may be exchanged with a power meter, which even more simplifies the measurement and data analysis.…”

“…The sodium terbium fluoride (NTF) [50,119] and the potassium terbium fluoride (KTF) crystals [72,120,121] also deserve attention: although they possess ∼20% lower Verdet constant, they exhibit a higher FOM parameter than the TGG crystal. Notable characteristics were recently reported for the rare-earth (RE) sesquioxide ceramics (RE 2 O 3 ; RE = Tb [122][123][124][125][126][127], Dy [48,[128][129][130] or Ho [47,[131][132][133]), which possess high concentrations of the magnetically-active RE 3+ ions. Among these, Tb 2 O 3 holds the record Verdet constant (∼3.5 times higher than TGG), followed by the Dy 2 O 3 (∼2 times higher (at 633 nm wavelength)) and Ho 2 O 3 (∼1.4 times higher (at 1064 nm wavelength)).…”

Self-propagating high-temperature synthesis of (Ho1-xLax)2O3 nanopowders for magneto-optical ceramics

“…Potentially, such materials can be other oxides of rare-earth (RE) elements. For example, it has been recently demonstrated that holmium oxide ceramics, in comparison with the TGG, have 1.3 times greater value of the Verdet constant [3, 4]. On the other hand, the rare-earth sesquioxides single crystals are extremely difficult to grow with common techniques, since most of the oxides undergo phase transformations upon heating – cooling process, which could lead to damage of the crystals [5].…”