Systems and methods for providing a microwave-to-optical (M2O) transducer using magneto-optical field interactions with spin states of an ensemble of ions doped into a crystal structure is presented. According to one aspect, the crystal structure is a (.sup.171Yb.sup.3+:YVO) doped crystal structure that provides a substrate for an on-chip implementation of the transducer. According to one aspect, coupling of microwave and optical signals to the ions is based on respective microwave and optical waveguides fabricated in or on the doped crystal structure. According to another aspect, coupling of microwave and optical signals to the ions is based on respective microwave and optical resonant cavities fabricated in or on the doped crystal structure. Transduction can be based on either a three-level system with near-zero applied external magnetic field or on a four-level system with zero applied external magnetic field. The transducer can operate reversibly as an optical-to-microwave (O2M) transducer.

The invention relates to a magneto-optical light modulator (100) for modulating light based on a physical property provided as an input to the modulator (100), the modulator (100) comprising a substrate (114) with a region of material (130) comprising a film of Eu.sub.(1-x)Sr.sub.(x)MO.sub.3 (112), an optical waveguide (106; 108) adapted for directing light through the region of material (130) and a first control unit, the first control unit being adapted to—maintain the region of material (130) at a constant predefined temperature in case the physical property is an input magnetic field subject to the region of material (130) or—maintain the region of material (130) subjected to a constant predefined magnetic field in case the physical property is an input temperature of the region of material (130), the light modulator (100) being adapted to perform the modulation of the light using the birefringence of the region of material (130), the birefringence depending on the physical property.

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.

A transparent ceramic material is manufactured by molding a source powder into a compact, the source powder comprising a rare earth oxide consisting of at least 40 mol % of terbium oxide and the balance of another rare earth oxide, and a sintering aid, sintering the compact at a temperature T (1,300 C.T1,650 C.) by heating from room temperature to T1 (1200 C.T1T) at a rate of at least 100 C./h, and optionally heating from T1 at a rate of 1-95 C./h, and HIP treating the sintered compact at 1,300-1,650 C. The ceramic material has improved diffuse transmittance in the visible region and functions as a magneto-optical part in a broad visible to NIR region.

The present invention relates to a security medium in which a color code for security information is printed on the surface of the medium using magnetically color tunable photonic crystal ink (MTX), wherein the color code is a color, pattern, image and/or data printed by the magnetic color variable ink, the color, pattern, image, and/or data are changed and appear, according to an observation angle, and the color, pattern, image and/or data appearing at at least one specific observation angle is information obtained by decoding the color code.

A transparent ceramic material is manufactured by molding a source powder into a compact, the source powder comprising a rare earth oxide consisting of at least 40 mol % of terbium oxide and the balance of another rare earth oxide, and a sintering aid, sintering the compact at a temperature T (1,300 C.T1,650 C.) by heating from room temperature to T1 (1200 C.T1T) at a rate of at least 100 C./h, and optionally heating from T1 at a rate of 1-95 C./h, and HIP treating the sintered compact at 1,300-1,650 C. The ceramic material has improved diffuse transmittance in the visible region and functions as a magneto-optical part in a broad visible to NIR region.

A magnetic field sensor comprises a magnetically responsive light propagating component configured to cause a polarization of light propagating inside the component to be rotated in response to an applied magnetic field, wherein the magnetically responsive light propagating component is formed of a bulk material doped with a dopant, the dopant including at least gadolinium, the dopant concentration being at a sufficiently low concentration such that the dopant is uniformly dispersed in the bulk material to provide a high Verdet constant. The magnetic field sensor also comprises a detector, and a polarization-maintaining light input device to couple the light into the magnetically responsive light propagating component. The detector is configured to measure a property of light output from the magnetically responsive light propagating component to determine a change in polarization of the light, the change caused by the presence of a magnetic field.

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.

Provided is a glass material that can satisfy both high Faraday effect and high light transmittance at wavelengths used. A glass material containing, in terms of % by mole of oxide, more than 40% Tb.sub.2O.sub.3 and having a percentage of Tb.sup.3+ of 55% by mole or more relative to a total content of Tb.

A high power Faraday isolator or rotator includes, at least one Faraday optical element, and a magnetic structure capable of generating a magnetic field within the at least one Faraday optical element. The at least one Faraday optical element comprises a Potassium Terbium Fluoride (KTF) crystal grown or manufactured along the [113] crystal orientation and which is oriented such that the light propagating through the Faraday isolator is within 2 degrees of the [113] crystal orientation.