Provided is a glass composition that exhibits greater Faraday effect than ever before. A glass composition contains 48% or more of Tb.sub.2O.sub.3 (exclusive of 48%) in % by mole.

An object of the present invention is to provide a new nanogranular structure material having magneto-optical properties different from those of existing nanogranular structure materials, and a method for producing the same. The nanogranular structure material has a composition represented by L-M-F—O wherein L is at least one element selected from the group consisting of Fe, Co, and Ni, and M is at least one element selected from the group consisting of Li, Be, Mg, Al, Si, Ca, Sr, Ba, Bi, and rare earth elements, F is fluorine, and O is oxygen. The nanogranular structure material according to the present invention is composed of a matrix formed of a fluorine compound having a composition represented by M-F and metal oxide nanoparticles dispersed in the matrix and having a composition represented by L-O.

A Faraday rotator and an optical isolator having a high transmittance and a high Verdet constant are provided. The optical isolator includes at least a Faraday rotator that rotates a polarization plane of incident light in a non-reciprocal manner, a polarizer disposed on a light incident side of the Faraday rotator, and an analyzer disposed on a light exit side of the Faraday rotator. The Faraday rotator is made of an oxide containing ytterbium oxide (Yb.sub.2O.sub.3), and is manufactured by a ceramic manufacturing process, wherein the oxide is allowed to contain an oxide of a metal other than ytterbium, and the proportion of ytterbium in all metal atoms in the oxide is 80% or more.

A paramagnetic garnet-type transparent ceramic is a sintered body of complex oxide represented by the following formula (1), comprising SiO.sub.2 as a sintering aid in an amount of more than 0% by weight to 0.1% by weight or less, and has a linear transmittance of 83.5% or more at the wavelength of 1,064 nm for an optical path length of 25 mm:
(Tb.sub.1-x-yY.sub.xSc.sub.y).sub.3(Al.sub.1-zSc.sub.z).sub.5O.sub.12  (1)
wherein 0.05≤x<0.45, 0<y<0.1, 0.5<1−x−y<0.95, and 0.004<z<0.2.

Provided is a glass material having a high light transmittance in a short wavelength range and easily producible. A glass material contains, in terms of % by mole, 5 to less than 30% Pr.sub.2O.sub.3 and 0.1 to 95% B.sub.2O.sub.3.

A paramagnetic garnet-type transparent ceramic characterized by being a sintered body of a terbium-containing composite oxide represented by formula (1) in which the linear transmittance at a wavelength of 1,064 nm at an optical path length of 15 mm is 83% or higher.
(Tb.sub.1-x-ySc.sub.xCe.sub.y).sub.3(Al.sub.1-zSc.sub.z).sub.5O.sub.12  (1)
(In the formula, 0<x<0.08, 0≤y≤0.01, 0.004<z<0.16.)

Exemplary arrangements relate to methods for recording and reproducing holograms. A method of recording a hologram in a thresholded opto-magnetic medium (7) includes producing a collimated recording beam (1) with a pulsed laser. The intensity of the recording beam is selectively modulated by passage through a modulator (2). The recording beam is spatially shaped by passage through a shaping element (15). The shaped modulated recording beam is made convergent by passage through an aspheric lens (4). The convergent beam is deflected bidirectionally with a MEMS mirror (6) that is in operative connection with the modulator, such that multiple disposed locations on a surface of the medium are exposed to a constriction of the convergent shaped recording beam, causing a change in the medium in the locations. Reconstructing the hologram is carried out by illuminating the medium with a collimated laser beam and focusing with a lens, light from the illuminated medium onto a detection matrix. Additional methods of recording and reproducing holograms utilize alternative steps.

Embodiments of synthetic garnet materials having advantageous properties, especially for below resonance frequency applications, are disclosed herein. In particular, embodiments of the synthetic garnet materials can have high Curie temperatures and dielectric constants while maintaining low magnetization. These materials can be incorporated into isolators and circulators, such as for use in telecommunication base stations.

An article includes a reflector having a first surface, a second surface opposite the first surface, and a third surface; and a first selective light modulator layer external to the first surface of the reflector; wherein the third surface of the reflector is open. A method of making an article is also disclosed.

A bismuth-substituted rare earth iron garnet single crystal suitable for Faraday rotators and optical isolators with reduced insertion loss due to suppressed valence fluctuation of Fe ions is provided. The bismuth-substituted rare earth iron garnet single crystal of the present invention is characterized by the composition formula (Gd.sub.aLn.sub.bBi.sub.cMg.sub.3−(a+b+c))(Fe.sub.dGa.sub.eTi.sub.fPt.sub.5−(d+e+f))O.sub.12. In the composition formula above, 0.02≤f≤0.05, 0.02≤{3−(a+b+c)}≤0.08, and −0.01≤{3−(a+b+c)}−{f+5−(d+e+f)}≤0.01. Ln is a rare earth element and may be selected from Eu, Dy, Gd, Ho, Tm, Yb, Lu, and Y.