Hitachi, Ltd.

Hitachi-lg Data Storage, Inc.

Hgst Netherlands, B.v.

Masaki Mukoh

Harukazu Miyamoto

Tatsuro Ide

Kentaro Osawa

Hiroyuki Minemura

Yasuhiko Iwanabe

Hisako Takei

Akemi Hirotsune

Yumiko Anzai

Takeshi Hoshino

Youichi Horii

Hiroko Sukeda

Rieko Otsuka

A luminous flux including laser light of different wavelengths outgoing from a light source unit is split into two luminous fluxes, the first luminous flux is focused on a sample with an objective lens, and the second luminous flux functions as reference light without radiating it onto the sample. Signal light reflected from the sample and the reference light are multiplexed by a polarized beam splitter and are made to interfere on four photodetectors out of phase in a photodetection unit. A signal processing unit acquires the optical axis distribution of an object in the sample by using the outputs of the plural photodetectors for every input wavelength, acquiring a detection signal and calculating the ratio of intensities of the detection signals at the different input wavelengths for every position in the sample.

Optical tomograph and optical tomographic method

There is provided an optical tomographic observation device which has a resolving power which is higher than those of a conventional optical tomographic observation device and a confocal microscope by a simple configuration by applying a homodyne phase diversity detection technology and designing so as to satisfy the following formula when &#x3bb; is a wavelength of a laser light source, &#x394;&#x3bb; is a wavelength half width at half maximum, NA is a numerical aperture of an objective optical element, S is an effective area of a photodetector, and M is a detection magnification of a detection surface relative to a condensing surface. 

Optical coherence tomography with homodyne-phase diversity detection

A beam emitted from a light source is split into a probe beam that irradiates a measurement object and a reference beam that does not irradiate the measurement object. A signal beam obtained by the reflection of the probe beam is split into first and second split signal beams, which are mutually orthogonal polarized components. The first split signal beam and the reference beam are inputted to a first coherence optical system to cause the beams to interfere with each other to generate at least three coherence beams differing in phasic relationship. The second split signal beam and the reference beam are inputted to a second coherence optical system to cause the beams to interfere with each other to generate at least three coherence beams differing in phasic relationship. The coherence beams are then detected.

Polarization-sensitive optical measurement instrument

A HAMR head includes an anti-reflecting (AR) coating on a side opposite (e.g., a flex side) of the air bearing surface (ABS). The anti-reflective coating may include one or more anti-reflective layers. The anti-reflective coating reduces the amount of light reflected back towards a light source unit. A shading layer may be disposed on the anti-reflective coating and may function as a contact electrode as well as reducing stray light escaping from the laser, thus reducing the amount of stray light reaching the ABS.

Head gimbals assembly, method for manufacturing thermal-assisted magnetic recording and manufacturing equipment of thermal-assisted magnetic recording

Embodiments of the present invention generally relate to a HAMR head. The HAMR head includes an anti-reflecting (AR) coating on a side opposite (e.g., a flex side) of the air bearing surface (ABS). The anti-reflective coating may include one or more anti-reflective layers. The anti-reflective coating reduces the amount of light reflected back towards a light source unit. A shading layer may be disposed on the anti-reflective coating and may function as a contact electrode as well as reducing stray light escaping from the laser, thus reducing the amount of stray light reaching the ABS.

The wavelength is monitored using a spectrum analyzer in a state where a semiconductor laser is being driven while changing the light-emitting time of the semiconductor laser. When the internal temperature of the semiconductor laser estimated from a measured wavelength falls out of a preset temperature range, a gimbal assembly is identified as a defective product.

Apparatus and method for inspecting thermally assisted magnetic head

An information reproducing method using PRML technology which provides asymmetry compensation and also assures media interchangeability. To compensate for asymmetry, target levels are basically adapted to readout signals and either restriction type (1) (time reversal and level reversal symmetry) or restriction type (2) (time reversal symmetry) is imposed between target levels. As a consequence, asymmetry compensation is made regardless of a readout signal distortion such as mark shift which might deteriorate media interchangeability.

PRML (Partial Response Maximum Likelihood) information reproducing method and information reproducing apparatus for implementing the same

An information recording medium capable of displaying multiple labels and a storing case for the information recording medium are provided. The multiple labels are displayed by changing the labels to be displayed while selectively selecting information layers in a multi information recording medium. The medium has a function to receive either voltage or current, and the information layers selectively receive either voltage or current for changing the labels.

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Tokyo, Japan

Masaki Mukoh