Tdk Corporation

Olympus Corporation

Other

The University of Tokyo

Takuya Tsukagoshi

Jiro Yoshinari

Tetsuro Mizushima

Hideaki Miura

Koji Mishima

Hiroshi Shingai

Daisuke Yoshitoku

Tsuyoshi Komaki

Hideki Hirata

Hajime Utsunomiya

Naoki Hayashida

Masanori Kosuda

Kimihiko Nishioka

Takashi Kikukawa

Lambertus Hesselink

Mark E McDonald

Andrew J Daiber

Yusuke Takei

Yasuo Sasaki

Michael V Morelli

Kiyoshi Matsumoto

Sergei L Sochava

Isao Shimoyama

Yuichi Sato

Koichi Karaki

Tokuyuki Honda

Rie Ihara

Kentaro Noda

Yoshiharu Ajiki

Hideki Sunohara

Sanjoy Ghose

Shunichi Nishimura

Tetsuro Kan

Yoichi Nakayama

Provided is a scanning near-field optical microscope capable of obtaining, in a highly sensitive manner, optical information having a spatial frequency higher than a spatial frequency corresponding to a wavelength of irradiation light. A scanning near-field optical microscopeaccording to the present invention includes: a light irradiating partfor emitting illumination light toward a samplea light receiving partfor receiving light; a microstructure for generating or selectively transmitting near-field light, the microstructure being disposed on at least one of an emission side of the light irradiating partand an incident side of the light receiving partand an ultrahigh-wavenumber transmitting mediumfor transmitting near-field light, the ultrahigh-wavenumber transmitting medium exhibiting anisotropy in permittivity or permeability.

Near-field optical microscope, near-field optical probe, and sample observation method

The present invention provides a hologram recording material which attains high refractive index change, high flexibility, high sensitivity, low scattering, environment resistance, durability, low dimensional change and high multiplicity, and is suitable for volume hologram recording. Also, the present invention provides a hologram recording medium. A hologram recording material comprising: an organometallic compound at least containing at least two kinds of metals, oxygen, and an aromatic group and having an organometallic unit wherein two aromatic groups are bonded directly to one metal; and a photopolymerizable compound. One of the at least two kinds of metals is Si, and the metal(s) other than Si is/are preferably selected from the group consisting of Ti, Zr, Ge, Sn, Al and Zn. The organometallic unit is preferably a unit wherein two aromatic groups are bonded directly to one Si atom. A hologram recording medium () has a hologram recording material layer ().

Hologram recording material and hologram recording medium

The present invention provides a hologram recording material which is not required to be subjected to pre-exposure treatment at the time of recording, attains high refractive index change, high sensitivity, low scattering, environment resistance, durability, low dimensional change, and high multiplicity, and is suitable for volume hologram recording. Also, the present invention provides a hologram recording medium. A hologram recording material comprising a matrix material having a softening temperature of 50&#xb0; C. or higher, and a photopolymerizable monomer which is in a liquid phase state at room temperature. The matrix material is preferably contained in an amount of 50% by weight or more and 90% by weight or less of the whole of the hologram recording material. A softening temperature of the hologram recording material is preferably 0&#xb0; C. or higher.

A holographic recording and reproducing apparatus includes a spatial light modulator, a Fourier transform lens, a reverse Fourier transform lens, a Charge Coupled Device (CCD) image sensor, and a pinhole disposed at a confocal point of the Fourier transform lens and the reverse Fourier transform lens, the holographic recording medium being disposed between the Fourier transform lens and the reverse Fourier transform lens, and the focal length of the Fourier transform lens and focal length of the reverse Fourier transform lens being different from each other, and the pinhole being disposed between the holographic recording medium and the Fourier transform lens or between the holographic recording medium and the reverse Fourier transform lens.

Holographic recording and reproducing apparatus

An optical recording medium including three or more recording layers is provided. The optical recording medium includes an L0 layer, an L1 layer, an L2 layer, and an L3 layer as the recording layers and first to third light transmitting spacer layers respectively arranged between the recording layers. A refractive index nof the third light transmitting spacer layer is set to satisfy n&#x3c;nwith respect to a refractive index nof the first and second light transmitting spacer layers. Thus, an effect of crosstalk light during reproduction can be reduced.

Optical recording medium

A holographic multiplex recording method which can keep a recording data rate constant and equalize nonuniformity in recording due to vibrations or the like, and a holographic recording apparatus and a holographic recording medium, which employ the method. In a process of multiplex-recording information, the time of exposure to a laser beam per data page is kept constant, and the laser output power of the laser beam is increased in accordance with a decrease in recording sensitivity of the holographic recording medium.

Holographic multiplex recording method, holographic recording apparatus and holographic recording medium employing the method using interference fringes

A holographic recording method, a holographic recording apparatus, a holographic recording and reproducing method, a holographic recording and reproducing apparatus, and a holographic recording medium for recording information in an angle multiplex fashion as a hologram in a first format in which either one of signal light and reference light branched out from a laser light source is made to cross the other in a recording layer at a predetermined incidence angle and the incidence angle is changed at a predetermined angular pitch, or in a second format of higher angular selectivity, wherein the incidence angle when recording information in the second format of higher angular selectivity can be adjusted to cover an incidence angle that satisfies the Bragg's condition when recording in the first format, thereby ensuring reproduction compatibility between media of different angular selectivities.

Holographic recording method, holographic recording apparatus, holographic recording and reproducing method, holographic recording and reproducing apparatus, and holographic recording medium

An optical recording medium has a plurality of information layers which are placed between a substrate and an optically transparent cover layer with optically transparent spacer layers interposed between the information layers. From among the plurality of information layers, the information layer excluding the information layer arranged closest to the substrate and the information layer adjacent to the information layer closest to the substrate has asymmetrical reflection characteristics in which reflectance on the substrate side when light incident from the substrate side is reflected on the information layer toward the substrate side is lower than the reflectance on the cover layer side when light incident from the cover layer side is reflected on the information layer toward the cover layer side.

A holographic recording apparatusrealizes multilevel gray-scale recording by: controlling a reflection type spatial light modulator (DMDD) via a control unitso that an object beam in an object optical systemis reflected in an exposure direction so as to be incident on a holographic recording mediumor in a non-exposure direction so as not to be incident thereon selectively pixel by pixel in accordance with a data page to be recorded; and making (N+1) levels of gradation exposure with a single exposure time tgiven by dividing tby N, where tis an exposure time necessary for rendering a single pixel of the data page as an ON pixel, and N is an integer of not less than 2.

Holographic recording method and holographic recording apparatus

A multilayer holographic recording medium that improves recording density and data transfer rates. The multilayer holographic recording medium, from which information is reproduced by a multilayer holographic memory reproducing apparatus, includes a plurality of deposited holographic recording layers. During recording, a reference beam is common to those holographic recording layers and an incident angle of an object beam is modulated for each holographic recording layer. During reproduction, a laser beam for reproduction having the same condition as that of the reference beam used for recording is projected thereonto, so that diffraction beams are simultaneously generated in the respective holographic recording layers to directions that are the same as incident directions of the object beam used for recording.

Multilayer holographic recording medium and manufacturing method of the same, multilayer holographic recording and reproducing method, multilayer holographic memory reproducing apparatus, and multilayer holographic recording and reproducing apparatus

In a personal identification systemfor identifying a user on the basis of biometric information, a hologram is formed in a holographic recording portionof an optical information recording medium. The hologram is provided by the interference between a reference beam subjected to spatial light modulation by record cryptographic identification information based on the biometric information of the user obtained by a biological information sensorand an object beam. At the time of identification, an information processing devicemakes validation cryptographic identification information from the biometric information directly obtained from the user, and a spatial light modulatormodulates a hologram reproduction reference beam by the validation cryptographic identification information. The right or wrong of a reproduced image is detected, and the leakage of the identification information is prevented.

Personal identification method, personal identification system, and optical information recording medium

Provided is a hologram retrieval method and a holographic recording and reproducing apparatus for preventing an increase in SNR, a decrease in retrieval accuracy, or the retrieval itself from being made impossible, which would otherwise occur because of a small size of data used for retrieval. Digital information is recorded on a holographic recording medium as data pages DP formed of a two-dimensional bit map image with each page being multiplexed. The data page DP is divided into a plurality of equal data blocks DBto, DBto DB, and DBto DB, and each data block DB is provided with a data image that is encoded by an encoding method for providing a certain number of ON pixels within each data block DB. A spatial light modulator allows the to-be-retrieved data image to be encoded by the encoding method and displayed as block information on a retrieval data block associated with the data block, and a signal beam to be thereby modulated. Of resulting diffracted beams, the diffracted beam of the maximum intensity is used to detect the target data image and the address of the reference beam.

Hologram retrieval method and holographic recording and reproducing apparatus

When recording on a holographic recording medium by using a recording beam, the time required for an asking servo control to recover is reduced to increase the data transfer rate. In the holographic recording apparatus, a laser beam from a laser light sourceis formed into a collimated beam having an expanded beam diameter and then is divided into an object beam and a reference beam. The divided object beam is modulated according to information to be recorded, and these object and reference beams are made incident on the reflective surface of a rotating polygon mirror, while maintaining collimated beam shapes and being adjacent to each other, through a condenser lenshaving a focal point behind the reflective surface of the polygon mirror. The object and reference beams are made incident on the holographic recording mediummoving in the same direction as their scanning direction with angles different from each other so as to interfere with each other within the holographic recording medium

Holographic recording method and apparatus

A holographic recording medium in which a thick holographic recording layer is formed without the use of multilayering and without accompanying thickness unevenness, scattering, and nonuniformity of dynamic range, and a method for manufacturing the same. The holographic recording mediumis configured by sandwiching a hybrid material layerand a photopolymer layerbetween first and second substratesand. The hybrid material layercontains an inorganic glass and a photopolymer as main ingredients. The photopolymer layersubjected to heat or ultraviolet curing is provided on the dried hybrid material layersuch that the combined thickness of this hybrid material layerand the photopolymer layeris uniform. The second substrateis bonded and fixed to this photopolymer layerserving as a bonding layer.

Holographic recording medium and method for manufacturing the same

A multilayer optical recording medium comprises four recording layers including an L0 layer, an L1 layer, an L2 layer, and L3 layer laminated between a substrate and an optically transparent cover layer and optically transparent spacer layers each provided between the recording layers. The L2 layer has the negative dependence of the reflectance on the incident angle of a laser light beam for reproduction. Crosstalk can be effectively reduced by the relation between the configuration of the respective recording layers and the crosstalk.

Growing community of inventors

Sagamihara, Japan

Takuya Tsukagoshi