Ricoh Company, Ltd.

Atsuyuki Watada

Motoharu Tanaka

Toshiaki Tokita

Hitoshi Nakamura

Fumiya Omi

Shunichi Sato

Naoto Jikutani

Takuro Sekiya

Satoru Sugawara

Takashi Takahashi

Akihiro Itoh

Akira Sakurai

Kazuya Miyagaki

Koei Suzuki

Ken Kanai

Hazime Machida

Masayoshi Katoh

Shinji Satoh

Shuuichi Hikichi

Teruyuki Furuta

Yoshitaka Hayashi

Noboru Sasa

Nobuyuki Koinuma

Toshishige Fujii

Hisamitsu Kamezaki

Kawori Tanaka

Yoshiko Kurosawa

Hirotaka Komoda

Hiroshi Deguchi

Fumiya Ohmi

Yasuo Sawada

Masaetsu Takahashi

Hajime Machida

Yuziro Kaneko

A surface-emission laser diode includes a distributed Bragg reflector tuned to wavelength of 1.1 &#x3bc;m or longer, wherein the distributed Bragg reflector includes an alternate repetition of a low-refractive index layer and a high-refractive index layer, with a heterospike buffer layer having an intermediate refractive index interposed therebetween with a thickness in the range of 5-50 nm.

Surface-emission laser diode operable in the wavelength band of 1.1-1.7 micrometers and optical telecommunication system using such a laser diode

For recording information at high density even at blue-laser wavelengths, a write-once-read-many optical recording medium includes a first inorganic thin film and at least one of a second inorganic thin film and an organic thin film, in which the first inorganic thin film contains at least 'R' and 'O,' wherein &#x201c;R&#x201d; is at least one selected from Y, Bi, In, Mo, V and lanthanum series elements; and &#x201c;O&#x201d; is oxygen atom, and the second inorganic thin film and the organic thin film are capable of suppressing at least one of deformation and breakage of the first inorganic thin film and receiving the change of state of the first inorganic thin film.

Write-once-read-many optical recording media and process for recording and reproducing information on the media

A surface-emission laser diode includes a distributed Bragg reflector tuned to wavelength of 1.1 &#x3bc;m or longer, wherein the distributed Bragg reflector includes an alternate repetition of a low-refractive index layer and a high-refractive index layer, with a heterospike buffer layer having an intermediate refractive index interposed therebetween with a thickness in the range of 5&#x2013;50 nm.

Surface-emission laser diode operable in the wavelength band of 1.1-1.7mum and optical telecommunication system using such a laser diode

Surface-emission laser diode operable in the wavelength band of 1.1-7&#x3bc;m and optical telecommunication system using such a laser diode

A magneto-optical recording medium includes a recording layer which is composed of A memory layer comprising a ferromagnetic layer with perpendicular anisotropy, and an auxiliary layer comprising antiferromagnetic layer which exhibits an antimagnetic phase at room temperature, and a ferromagnetic phase at temperatures near the Curie temperature of the memory layer which is higher than room temperature, because of the occurrence of magnetic phase transformation, with the memory layer and the auxiliary layer being overlaid. A magneto-optical recording method using this magneto-optical recording medium is described.

Magneto-optical recording medium and recording method using the same

A magneto-optical recording method for recording information in an overwrite mode in a magneto-optical recording medium by the application of a laser beam is disclosed. The magneto-optical recording medium includes a substrate, and at least two magnetic recording layers overlaid thereon, with an exchange force working at least between the two magnetic recording layers, and the Curie temperature of each of the two magnetic recording layers being substantially the same. The magneto-optical recording method includes the step of conducting overwriting information by changing the power of the laser beam to be applied to at least two different levels, one at which the magnetic recording layers are heated to a temperature near or higher than the Curie temperature, and the other at which the magnetic recording layers are heated to a temperature lower than the Curie temperature, while a magnetic field is applied to the magneto-optical recording medium in one direction, in accordance with signals to be recorded in the magneto-optical recording medium, and this recording method requires only one initialization by the application of the magnetic field, but does not require any further initialization thereafter.

Magneto-optical recording medium having two magnetic layers with the

A magneto-optical recording method is capable of carrying out overwriting on a magneto-optical recording medium including a single perpendicular magnetic layer serving as a recording layer, by applying laser beams thereto, thereby controlling the formation and erasure of magnetic domains, in which a magnetic domain with a desired length can be formed or erased by the application of a plurality of laser beams during the formation and erasure of the magnetic domains.

Magneto-optical recording method

A magneto-optical recording method capable of overwriting on a magneto-optical recording medium is disclosed. The magneto-optical recording medium includes a recording layer comprising a single magnetic layer with magnetic anisotropy and the magneto-optical recording methods includes the step of applying a laser beam with a light power level P.sub.1 to the recording layer when a binary coded signal '1' is written therein under a fixed external magnetic field; and the steps of applying a laser beam with a light power level Poh to the recording layer and successively applying a laser beam with a light power level Pol to said recording layer when a binary coded signal '0' is written therein under a fixed external magnetic field, wherein Pol, P.sub.1 and Poh are in the relationship of O&lt;Pol&lt;P.sub.1 &lt;Poh.

Magneto-optical recording medium

A magneto-optical recording medium is composed of a first magnetic layer and a second magnetic layer, which are overlaid, each having a perpendicular magnetic anisotropy, and the first magnetic layer having a Curie temperature of Tc.sub.1, a saturation magnetization of Ms.sub.1, a coercive force of Hc.sub.1, and a thickness of t.sub.1, the second magnetic layer having a compensation temperature of Tcomp.sub.2, a Curie temperature Tc.sub.2, and a coercive force of Hc.sub.2, and which satisfies the relationships:

Magneto-optical recording medium having first and second magnetic layers

Magneto-optical recording method and magneto-optical recording medium

A magneto-optical recording method capable of overwriting on a magneto-optical recording medium is disclosed. The magneto-optical recording medium includes a recording layer comprising a single magnetic layer with magnetic anisotropy and the magneto-optical recording methods includes the step of applying a laser beam with a light power level P.sub.1 to the recording layer when a binary coded signal '1' is written therein under a fixed external magnetic field; and the steps of applying a laser beam with a light power level Poh to the recording layer and successively applying a laser beam with a light power level Pol to said recording layer when a binary coded signal '0' is written therein under a fixed external magnetic field, wherein Pol, P.sub.1 and Poh are in the relationship of 0&lt;Pol&lt;P.sub.1 &lt;Poh.

Magneto-optical recording method and recording medium for use in the same

A magneto-optical recording method is disclosed, by which a magnetic recording pattern is formed in an overwriting mode, utilizing demagnetizing field, by directing a light beam onto a perpendicularly magnetized film layer of a magneto-optical recording medium, wherein when recording is being carried out by the application of a light beam onto the perpendicularly magnetized film layer, on switching the direction of magnetization for recording from downward to upward or from upward to downward, when required, with respect to the surface of the magnetized film layer, a light beam application mode for a light-beam applied portion in the magnetized film layer to which the light beam has been applied, and a light beam application mode in a portion in the magnetized film layer immediately after the light-beam applied portion to which the light beam is yet to be applied, are changed.

Magneto-optical recording method with switching and maintaining

A magneto-optical recording material is disclosed, which consists of magnetoplumbite type ferrite containing barium in which part of Ba is replaced by La and part of Fe is replaced by Co.

Magneto-optical recording material

This invention provides a metal oxide magnetic substance represented by the following general formula:

Metal oxide magnetic substance and a magnetic film consisting thereof

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Kawasaki, Japan

Atsuyuki Watada