Ngk Insulators, Inc.

Hiroaki Abe

Yoshinari Kozuka

Takayuki Sekiya

Yukihisa Osugi

Shuhei Toyoda

Yuichi Kakizaki

Disclosed herein is an optically active single crystal, which has both levo-rotatory portion and dextro-rotatory portion and is even in optical rotatory power and physical constants such as electrooptic constant and Farady constant. Its fabrication process is also disclosed, wherein a single crystal is grown in accordance with the crystal pulling method making use of a seed crystal comprising a levo-rotatory single crystal and a dextro-rotatory single crystal, which are joined to each other. The process permits fabrication of the above-mentioned optically active single crystal in a short period of time and with ease.

Optically active single crystal and fabrication process thereof

A spatial light modulating element including an electrooptic and photoconductive single crystal plate, a light-transmitting insulating layer provided on at least one of opposite surfaces of the electrooptic and photoconductive single crystal plate, and a pair of electrodes provided for applying an electric field to the insulating layer and the single crystal plate. The insulating layer is formed from a uniaxial single oxide crystal which is crystallographically oriented such that the insulating layer exhibits neither birefringence, nor an electrooptic effect in a direction of the electric field. The insulating layer may be a LiNbO.sub.3, LiTaO.sub.3 or TiO.sub.2 (rutile) single crystal plate cut normal to the (001)-axis.

Spatial light modulating element using uniaxial single crystal of oxide

An optical unit or an optical sensor through which a light beam is propagated in a predetermined direction, having an optical component which includes at least one first single crystal element each having a property of causing dextrorotation of a plane of polarization of the light beam during propagation of the beam, and at least one second single crystal element each having a property of causing levorotation of the plane of polarization of the light beam. The first and second single crystal elements are superposed on each other in a direction perpendicular to the direction of propagation of the beam. The single crystal elements may be bonded together by direct solid-solid reaction, or by diffusion of a material of a thin bonding film interposed between the adjacent single crystal elements. The single crystal elements also exhibit a magnetooptical or Faraday effect when used in a magnetic-field sensor, for example.

Optical component and magnetic-field sensor using superposed single

A method and an apparatus for measuring the strength of an AC electric field or an equivalent voltage, or the strength of an AC magnetic field or an equivalent current, based on a light beam which is transmitted through and thus modulated by an optical sensing head due to the Pockel's and Faraday effects, while the sensing head is exposed to the AC electric and magnetic fields. The sensing head includes an optical material which exhibits the Pockel's effect and an optical material which exhibits the Faraday effect, or includes an optical material which exhibits both the Pockel's and Faraday effects. The modulated beam is applied to a light-sensitive element, which produces an electric output signal. A first and a second component of the electric output signal are retrieved by respective detectors. The first component has a same frequency as that of the electric or magnetic field, while said second component has a frequency which is two times that of said electric or magnetic field. The electric field strength or the voltage, and the magnetic field strength or the current are determined by one and the other of the first and second components, respectively.

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Nagoya, Japan

Hiroaki Abe