An optical track format of a holographic storage optical disc includes a lead-in area, a data area and a lead-out area. The data area is provided with data holographic positioning marks for marking reading/writing position of data holograms on the optical track and start positioning marks for marking position on the optical track where data holograms start to be recorded. The start positioning marks may also contain address encoding information. Such optical track can be encoded by performing binary encoding by length of the optical track between two consecutive notches, or performing binary encoding by high and low levels of a level signal.

An optical track format of a holographic storage optical disc includes a lead-in area, a data area and a lead-out area. The data area is provided with data holographic positioning marks for marking reading/writing position of data holograms on the optical track and start positioning marks for marking position on the optical track where data holograms start to be recorded. The start positioning marks may also contain address encoding information. Such optical track can be encoded by performing binary encoding by length of the optical track between two consecutive notches, or performing binary encoding by high and low levels of a level signal.

An analysis device includes a controller configured to count a pulse derived from a particles as a plural particles when a light reception level signal includes the pulse having a first extreme value point, a second extreme value point, and a third extreme value point, and the pulse fulfils a condition in which the third extreme value point is present between the first extreme value point and the second extreme value point in a pulse width direction of the pulse, the third extreme value point is present between the first extreme value point and a threshold in a pulse amplitude direction, the first extreme value point and the second extreme value point are each an extreme value point of a waveform projecting in a common direction, and the third extreme value point is an extreme value point of a waveform in a direction opposite to the common direction.

An optical encoder disk comprising an opaque disk, an outer track adjacent a peripheral edge of the disk, an inner index track defined by a first pattern of radial light-blocking elements subtending an arc within an annular band interposed between the outbound track and an axis of the disk, and an opaque support pattern of non-radial elements located within the annular band outside of the arc in which the index track is located formed of substantially non-radial elements. The inner index track further includes pattern apertures formed through the disk between the light-blocking elements so that light emitted on one face of the disk passes through the pattern apertures and falls upon photodetectors located adjacent an opposite face of the disk.

An optical encoder disk comprising an opaque disk, an outer track adjacent a peripheral edge of the disk, an inner index track defined by a first pattern of radial light-blocking elements subtending an arc within an annular band interposed between the outbound track and an axis of the disk, and an opaque support pattern of non-radial elements located within the annular band outside of the arc in which the index track is located formed of substantially non-radial elements. The inner index track further includes pattern apertures formed through the disk between the light-blocking elements so that light emitted on one face of the disk passes through the pattern apertures and falls upon photodetectors located adjacent an opposite face of the disk.

An analysis device includes a controller configured to count a pulse derived from a particles as a plural particles when a light reception level signal includes the pulse having a first extreme value point, a second extreme value point, and a third extreme value point, and the pulse fulfils a condition in which the third extreme value point is present between the first extreme value point and the second extreme value point in a pulse width direction of the pulse, the third extreme value point is present between the first extreme value point and a threshold in a pulse amplitude direction, the first extreme value point and the second extreme value point are each an extreme value point of a waveform projecting in a common direction, and the third extreme value point is an extreme value point of a waveform in a direction opposite to the common direction.

Provided is an optical recording medium including two or more recording layers, and a light irradiation surface that is irradiated with light for recording an information signal on the two or more recording layers. Among the two or more recording layers, at least one layer other than a layer located on the deepest side from the light irradiation surface includes an oxide of a metal A, an oxide of a metal B, and an oxide of a metal C. The metal A is at least one kind among W, Mo, and Zr, the metal B is Mn, and the metal C is at least one kind among Cu, Ag, and Ni. Ratios of the metal A, the metal B, and the metal C satisfy a relationship of 0.46x1 (provided that, x1=a/(b+0.8c), a representing an atomic ratio [atom %] of the metal A with respect to the sum of the metal A, the metal B, and the metal C, b representing an atomic ratio [atom %] of the metal B with respect to the sum of the metal A, the metal B, and the metal C, and c representing an atomic ratio [atom %] of the metal C with respect to the sum of the metal A, the metal B, and the metal C.

Provided is an optical recording medium including two or more recording layers, and a light irradiation surface that is irradiated with light for recording an information signal on the two or more recording layers. Among the two or more recording layers, at least one layer other than a layer located on the deepest side from the light irradiation surface includes an oxide of a metal A, an oxide of a metal B, and an oxide of a metal C. The metal A is at least one kind among W, Mo, and Zr, the metal B is Mn, and the metal C is at least one kind among Cu, Ag, and Ni. Ratios of the metal A, the metal B, and the metal C satisfy a relationship of 0.46x1 (provided that, x1=a/(b+0.8c), a representing an atomic ratio [atom %] of the metal A with respect to the sum of the metal A, the metal B, and the metal C, b representing an atomic ratio [atom %] of the metal B with respect to the sum of the metal A, the metal B, and the metal C, and c representing an atomic ratio [atom %] of the metal C with respect to the sum of the metal A, the metal B, and the metal C.

There are provided an optical disk from which high-density data is reproduced and a reproduction apparatus that reproduces data from such an optical disk having high-density data recorded thereon. A photo-detecting section has two split detectors A and B in the direction of tracks on the disk. A signal processing section generates a TPP (Tangential Push-pull) signal made of a differential signal derived from detection signals from the detectors A and B, and further generates a reproduced signal by extracting from the TPP signal a high-frequency component signal in a record signal recorded on the disk. The signal processing section reconstitutes a high-frequency component signal in the record signal recorded on the disk by frequency-shifting the TPP signal obtained as a readout signal from a superimposed signal having the carrier signal and the record signal superimposed with each other.

There are provided an optical disk from which high-density data is reproduced and a reproduction apparatus that reproduces data from such an optical disk having high-density data recorded thereon. A photo-detecting section has two split detectors A and B in the direction of tracks on the disk. A signal processing section generates a TPP (Tangential Push-pull) signal made of a differential signal derived from detection signals from the detectors A and B, and further generates a reproduced signal by extracting from the TPP signal a high-frequency component signal in a record signal recorded on the disk. The signal processing section reconstitutes a high-frequency component signal in the record signal recorded on the disk by frequency-shifting the TPP signal obtained as a readout signal from a superimposed signal having the carrier signal and the record signal superimposed with each other.