Total Performance of Magneto-Optical Ceramics with a Bixbyite Structure

Abstract

High-quality magneto-optical ceramics (TbxY1−x)2O3 (x = 0.5–1.0) with a Bixbyite structure were extensively investigated for the first time. The total performances of these ceramics were far superior to those of commercial TGG (Tb3Ga5O12) crystal, which is regarded as the highest class of Faraday rotator material. In particular, the Verdet constant of Tb2O3 (when x = 1.0) ceramic was the largest—495 to 154 rad·T−1·m−1 in the wavelength range of 633 to 1064 nm, respectively. It was possible to further minimize the Faraday isolator device. The insertion loss of this ceramic was equivalent to that of the commercial TGG single crystal (0.04 dB), and its extinction ratio reached more than 42 dB, which is higher than the value for TGG crystal (35 dB). The thermal lens effect (1/f) was as small as 0.40 m−1 as measured by a 50 W fiber laser. The laser damage threshold of this ceramic was 18 J/cm2, which is 1.8 times larger than that of TGG, and it was not damaged during a power handling test using a pulsed laser (pulse width 50 ps, power density 78 MW/cm2) irradiated at 2 MHz for 7000 h.

Faraday Rotation of Dy2O3, CeF3 and Y3Fe5O12 at the Mid-Infrared Wavelengths

“…While a lot of scientific effort has been already put into the investigation of the magneto-active materials for the visible and near-IR wavelengths, the options for the mid-IR wavelengths are still very limited [ 18 ]. The materials used for the near-IR wavelengths usually include Tb ions (e.g., the terbium-based garnets, fluorides or sesquioxides have been reported [ 20 , 21 , 22 , 23 ]), which have strong absorption in the mid-IR and, therefore, cannot be used. For low-power mid-IR laser applications, the ferrimagnetic yttrium iron garnet Y Fe O (YIG) crystal and its rare-earth-substituted compositions may be used, as these possess a very high specific Faraday rotation and low saturation magnetization [ 13 , 24 ].…”

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

“…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)).…”

Fabrication and Magneto-Optical Properties of Yb2O3 Based Ceramics

“…The main efforts of researchers in the latter direction are aimed at developing new magneto-optical materials with better characteristics (high thermal conductivity and Verdet's constant, minimal absorption at operating wavelengths, etc.). Recently, ceramic technology for such material fabrication has been noted as one of the most promising developments, and on this basis a number of ceramics with unique characteristics have already been prepared [12][13][14][15][16]. Progress in development of large-size FIs, which are important for creation of high-power laser sources, can be related to use of rare-earth sesquioxides as a base material.…”