Abstract: A measurement apparatus includes a generator that causes electromagnetic waves to be incident on a sample, a receiver that receives electromagnetic waves reflected by the sample, and a controller that controls the generator and receiver. The sample includes a first layer on which the electromagnetic waves are incident and a second layer stacked on the first layer. The controller detects whether a third layer is present between the first and second layers based on the electromagnetic waves incident on the sample from the generator and the electromagnetic waves received by the receiver. The generator causes the electromagnetic waves to be incident at an angle such that the electromagnetic waves are totally reflected between the first and third layers and/or between the first and second layers.

Abstract: An optical navigation device includes a casing, a circuit board, an illumination light source and an optical receiver. The casing is movably located above a navigation surface. The circuit board is disposed inside the casing. The illumination light source is disposed on the circuit board and adapted to provide an illumination channel toward the navigation surface. The optical receiver is disposed adjacent to the illumination light source. An imaging channel of the optical receiver is substantially parallel to a planar normal vector of the navigation surface, and the optical receiver is adapted to identify features on the navigation surface within a range crossed by the imaging channel and the illumination channel for providing navigation information.

Abstract: One embodiment may provide a light source module including: a light source including at least one vertical cavity surface-emitting laser, which is configured to transfer light through N (N being a natural number equal to or greater than 1) apertures; at least one collimator lens through which light emitted from the light source passes; and a driving device configured to make the collimator lens move, wherein the at least one vertical cavity surface-emitting laser comprises divided regions, and an intensity of a beam is controlled according to a predetermined far-distance mode or near-distance mode.

Abstract: A recording head has a near-field transducer proximate a media-facing surface of the recording head. A waveguide overlaps and delivers light to the near-field transducer, the light having a near-infrared wavelength. Two subwavelength focusing mirrors are at an end of the waveguide proximate the media-facing surface. The subwavelength mirrors are on opposite crosstrack sides of the near-field transducer and separated from a peg of the near-field transducer by a gap. The subwavelength focusing mirrors each include a core having a first edge exposed at the media-facing surface. The core formed of a core material that is resistant to mechanical wear and corrosion, such as a dielectric or robust metal. A liner covers a second edge of the core facing the near-field transducer. The liner includes a plasmonic metal that is has a plasmonic frequency in the ultraviolet range.

Abstract: There is provided an illumination system of a navigation device including a light beam shaping optics, and a first light source and a second light source having different characteristics. The light beam shaping optics is used to shape light beams emitted by the first light source and the second light source to illuminate a work surface with substantially identical incident angles and/or beam sizes.

Abstract: There is provided an illumination system of a navigation device including a light beam shaping optics, and a first light source and a second light source having different characteristics. The light beam shaping optics is used to shape light beams emitted by the first light source and the second light source to illuminate a work surface with substantially identical incident angles and/or beam sizes.

Abstract: A laser beam irradiation apparatus including a laser source configured to emit light; a collimator configured to collimate the emitted light; a scanner configured to adjust the collimated light to change an irradiation direction thereof; a first lens part configured to focus the adjusted light to irradiate a laser beam on a sealing part; a camera configured to receive visible light passing through the scanner; a heat sensing part configured to receive infrared (IR) light passing through the scanner; and a control part configured to control a moving direction and an intensity of the laser beam.

Abstract: An illustrative example camera device includes a sensor that is configured to detect radiation. A first portion of the sensor has a first field of vision and is used for a first imaging function. A distortion correction prism directs radiation outside the first field of vision toward the sensor. A lens element between the distortion correcting prism and the sensor includes a surface at an oblique angle relative to a sensor axis. The lens element directs radiation from the distortion correcting prism toward a second portion of the sensor that has a second field of vision and is used for a second imaging function. The sensor provides a first output for the first imaging function based on radiation detected at the first portion of the sensor. The sensor provides a second output for the second imaging function based on radiation detection at the second portion.

Abstract: To reduce an influence of stray light and stably record/reproduce high-quality data in holographic recording/reproduction. A holographic memory device includes an optical system that guides a reference beam to an optical information recording medium at a desired angle of incidence, a control part that controls the angle of incidence of the reference beam generated in the optical system, and a lens part that images the reference beam in a desired position of the optical information recording medium. Further, at least a first light beam at a first angle and a second light beam at a second angle different from the first angle are output from the optical element, and the optical element is provided so that the first light beam may propagate within an effective diameter of the lens part and the second light beam may propagate to an outside of the effective diameter of the lens part.

Abstract: There is provided a system for inspecting an edge area of a transparent media, the transparent media having a decoration on a surface, the system includes: an illuminator to direct light to the transparent media for inspection, wherein the illuminator directs light to the transparent media at an oblique angle relative to a surface of the transparent media which is opposite the surface with the decoration; an optical element to capture light transmitted through the transparent media; and a sensor to obtain an image from the light captured by the optical element. There is also provided a method for inspecting an edge area of a transparent media, where the transparent media has a decoration on a surface.

Abstract: An optical pickup device has an astigmatism element which imparts astigmatism to reflected light of laser light reflected on a recording layer, and a spectral element into which the reflected light is entered, and which separates the reflected light. The spectral element is divided into four third areas by a first area having a certain width and formed along a straight line in parallel to a first direction, and by a second area having a certain width and formed along a straight line in parallel to a second direction. The spectral element is configured to guide the reflected light passing through the four third areas to respective corresponding sensors on a photodetector while making propagating directions of the reflected light different from each other, and to avoid guiding the reflected light entered into the first area and into the second area to the sensors.

Abstract: An optical pickup device includes an objective lens portion which converges laser light at a first focal point and a second focal point; an actuator which positions the first focal point or the second focal point on a recording layer in a disc; an astigmatism element which sets a first focal line position and a second focal line position of the laser light reflected on the disc away from each other in a propagating direction of the laser light; a spectral element which disperses four light fluxes obtained by dividing the laser light reflected on the disc in four from each other; and a photodetector having a sensor group which receives the four light fluxes dispersed by the spectral element.

Abstract: An optical pickup device preventing damage or performance degradation of a second optical system. The optical pickup device includes first laser light source emitting a first light beam having a first wavelength, a first optical system guiding the first light beam emitted from the first laser light source to a first optical disc. Further, the optical pickup device includes a DVD integration unit emitting a second light beam having a second wavelength different from the first wavelength, a second optical system guiding the second light beam emitted from the DVD integration unit to a second optical disc different from the first optical disc, and a filter disposed at a position blocking incident light, of an unwanted light beam having the first wavelength and derived from the first optical system, from entering into the second optical system, so as to block the first light beam having the first wavelength.

Abstract: An optical pickup device has an astigmatism element which imparts astigmatism to reflected light of laser light reflected on a recording layer, and a spectral element into which the reflected light is entered, and which separates the reflected light. The spectral element is divided into six second areas by a straight line in parallel to a first direction, a straight line in parallel to a second direction, and a first area having a predetermined width and formed along a straight line in parallel to a third direction inclined from the first direction by 45 degrees. The spectral element is configured to guide the reflected light passing through the six second areas to corresponding sensors on a photodetector while making propagating directions of the reflected light different from each other, and to avoid guiding the reflected light entered into the first area to the sensors.

Abstract: The present invention relates to an aberration correcting device comprising: an aberration correcting element which modulates the phase of incident light; and a position adjusting section which can move the aberration correcting element in a direction perpendicular to an optical axis of the incident light, wherein the aberration correcting element includes first and second aberration correction plates, each of which is disposed such that the phase of transmitted light beam differs with transmission position of the incident light beam with the same phase, and the aberration correcting element has a reference arrangement which is an arrangement of the first and second aberration correction plates in which the light beams transmitted through the aberration correcting element have the same phase, and assuming that a point on the first aberration correction plate crossing the optical axis is a point Oa and a point on the second aberration correction plate crossing the optical axis is a point Ob in the reference ar

Abstract: A thin-type optical head, smaller in optic mounting spaces comprising to the conventional one, in an optic system enabling with BD including a 2-layers BD, DVD an CD, comprises a light source, for emit a light beam therefrom; an optical branch element for penetrating a predetermined amount of lights, therethrough, of an incident light beam thereon, and to reflecting remaining amount of lights thereupon; a light focusing element for focusing the light beam upon an optical information recording medium; a photo detector for receiving the light beam reflecting upon the optical information recording medium; and an optical path converter element for converting an angle of an optical path, on which the light beam propagates, wherein the optical path converter element is disposed on an optical path of the light beam between the optical branch element and the photo detector, or between the optical branch element and the light source, and has an incident surface, upon which the light beam enters, and an emission surfac

Abstract: An optical head for recording or reproducing a signal on or from an optical recording medium including a light source, an objective lens for condensing light emitted from the light source to the optical recording medium, and a light-separating device arranged between the light source and the objective lens in order to separate the light reflected from the optical recording medium from the light emitted from the light source. The light-separating device includes a first glass, a multilayer film formed on the first glass, and an adhesive layer arranged on the multilayer film in order to bond a second glass onto the multilayer film. The majority of the light emitted from the light source enters into the light-separating device through the first glass and is reflected by the multilayer film.

Abstract: An optical pickup apparatus comprising: a collimating lens configured to convert laser light emitted from a laser diode, from diffused light into parallel light; an objective lens; and a prism configured to guide the laser light emitted from the collimating lens to the objective lens, the prism including: a first face that the laser light emitted from the collimating lens enters; a second face that reflects the laser light entering the first face; and a third face that reflects the laser light reflected from the second face in a direction of the second face, and emits the laser light reflected again from the second face in a direction of the objective lens.

Abstract: A lighting device, including a first light source emitting light of a first wavelength; a second light source close to the first source, emitting light of a second wavelength in almost a same direction as that of the first source; a third light source located emitting light of a third wavelength in a direction different from that of the first and second sources; a coupling optical system coupling light from the first and second sources; another coupling optical system coupling light from the third source; and a light path synthesizer synthesizing a light path of light from the first, second and third sources, wherein the light path synthesizer includes a first surface reflecting light from the first source and transmitting light from the second and third sources and a second surface unparallel with the first surface, reflecting light from the second source and transmitting light from the third source.

Abstract: An optical head device has at least one upward-reflecting mirror, objective lenses, an objective lens actuator, and a moving mechanism. The upward-reflecting mirror receives an incident luminous flux having a wavelength emitted from a semiconductor, and changes its direction. The objective lenses having mutually different numerical apertures condense the luminous flux whose direction has been changed by the upward-reflecting mirror to radiate a condensed luminous flux onto an information recording medium. The objective lens actuator moves the objective lenses in the focus direction of the information recording medium so that the luminous flux incident on the information recording medium attains a focused state. The moving mechanism moves the upward-reflecting mirror so that the luminous flux is incident on the information recording medium via any one of the objective lenses.

Abstract: The present invention relates to a beam shifting element and to an apparatus for reading from and/or writing to optical storage media using in such a beam shifting element. According to the invention, the beam shifting element has at least a first optical element for deflecting an incoming light beam by a first angle and a second optical element for deflecting the light beam coming from the first optical element by a second angle opposite to the first angle, wherein the first optical element and the second optical element are optical elements with an adjustable deflection angle.

Abstract: An optical information recording/reproducing device is provided with a first light source 20a for emitting recording light 22a, a second light source 20b for emitting reproducing light 22b, an objective lens 6 for focusing the emitted lights from the both light sources 20a, 20b on an information recording medium including a recording region 3 capable of three-dimensional recording and photodetectors 19a, 19b for detecting reflected lights 7a?, 7b? from the information recording medium, and records information on recording layers 1a to 1e utilizing a nonlinear absorption phenomenon. At the objective lens 6, an average rim intensity of the recording light 7a is lower than that of the reproducing light 7b.

Abstract: An optical pickup device radiates laser light to a disc having a plurality of recording layers in a direction of lamination. The optical pickup device includes an astigmatic element and a spectral element. The astigmatic element allows reflected light from the disc to converge in a first direction and form a first focal line at a first position, and allows reflected light to converge in a second direction and form a second focal line at a second position closer to the disc than the first position. The spectral element splits a reflected light flux in two along a straight line parallel to the first direction and turns traveling directions of the split two light fluxes into directions separated from each other. Here, the spectral element is interposed between the second focal line of the reflected light from a target recording layer and the second focal line of the reflected light from a deeper recording layer than the target recording layer.

Abstract: A holographic information recording and/or reproducing apparatus including: a light source unit emitting reference light and signal light; a first optical path guiding unit guiding the lights to cross; a second optical path guiding unit including a first polarization converter located on an optical path of one of the reference and signal lights, a first polarization beam splitter located at a crossing point of the reference light and the signal light, an optical path converter guiding the reference light and the signal light so that they cross again, a second polarization converter located on an optical path of the signal light before the signal light crosses the reference light, and a second polarization beam splitter uniting the optical paths of the reference light and the signal light; and an objective lens unit illuminating the reference light and the signal light onto one side of a holographic information storage medium.

Abstract: An optical integrated device includes a light source; a light splitting-and-guiding section that splits a reflected light beam into two end light beams, a connection light beam, and a residual light beam, and guides the two end light beams and the connection light beam in directions different from a direction of the residual light beam; and a light receiving section that receives the two end light beams and the connection light beam with photodetection devices divided, in the tangential direction, into at least two regions within a range in which the connection light beam is incident, receives the residual light beam with photodetection devices divided, in the tangential direction, into regions having widths corresponding to portions on which the two end light beams are incident, and outputs a detection signal in accordance with an amount of light received with each of the photodetection devices.

Abstract: An optical device for holographic recording or reading is provided and includes: a light emission unit that emits light to be irradiated on an optical recording medium, the light being recording or reading light; a first prism unit that moves in accordance with a moving speed of the optical recording medium and refracts the light to move the light irradiated on the optical recording medium over a distance in a moving direction of the optical recording medium so that the light is irradiated on substantially the same position on the optical recording medium for a period of time; and a second prism unit that moves in accordance with the moving speed of the first prism unit to compensate for an optical path length of the light.

Abstract: A near field optical disc and a near field optical disc reading apparatus are provided. The near field optical disc has at least one light source and a near field optical pick-up head, and the near field optical disc includes a light guiding substance, a first reflection layer and a second reflection layer. The light guiding substance has a first surface, a second surface opposite thereto and at least one light entrance window. Light emitted from the light source enters the light guiding substance through the light entrance window. The second reflection layer is disposed on the second surface. The first reflection layer is disposed on the first surface and has a plurality of light pervious holes. A part of the light is transmitted through the light pervious holes and picked up by the near field optical pick-up head.

Abstract: An optical recording head to record information onto a recording medium utilizing light including; a slider provided to move relatively to the recording medium; a light propagation element provided on a side surface of the slider substantially vertical against a recording surface of the recording medium so as to cause propagation of light incident with a predetermined angle to be irradiated on the recording medium; and, a prism provided on the light propagation element so as to oppose to the side surface of the slider having the light propagation element and to deflect the incident light to be incident into the light propagation element with a predetermined angle.

Abstract: An optical-pickup apparatus comprising: a polarization beam splitter fixed to a base, which includes a first prism that laser light emitted from a laser diode enters, a second prism that return light of the laser light reflected from a signal recording layer of an optical disc enters, and a control film that is formed on either one of opposed surfaces of the first and second prisms so that the laser light and the return light are selectively passed through or reflected from the control film, the opposed surfaces being opposed to each other; and first and second positioning pins provided on the base to position the polarization beam splitter, the polarization beam splitter being fixed to the base in a state where the opposed surface of at least one of the first and second prisms is made in contact with at least one of the first and second positioning pins.

Abstract: An adhesive positions a beam shaping element in such a manner as to satisfy the following relational expressions (1) and (2): 0<L??WA/(?·?·SAS)??(1) SAS=1000(0.5 m2+1.5m?2)[m?/mm]??(2), if it is assumed that m is the beam shaping magnification of a beam shaping element, L[mm] is the distance from a light source side surface of the beam shaping element to a center position of the adhesive, ?[1/K] is the linear expansion coefficient of a light source retaining holder, ?WA[m?] is amount of astigmatic aberration caused by the beam shaping element, and ?T[K] is an environmental temperature variation amount.

Abstract: An optical head for recording or reproducing a signal on or from an optical recording medium including a light source, an objective lens for condensing light emitted from the light source to the optical recording medium, and a light-separating device arranged between the light source and the objective lens in order to separate the light reflected from the optical recording medium from the light emitted from the light source. The light-separating device includes a first glass, a multilayer film formed on the first glass, and an adhesive layer arranged on the multilayer film in order to bond a second glass onto the multilayer film. The majority of the light emitted from the light source enters into the light-separating device through the first glass and is reflected by the multilayer film.

Abstract: An optical head includes: a first optical element having an optical characteristic of reflecting a light of a first wavelength and transmitting lights of second and third wavelengths, on the first optical element the light of the first wavelength from a first light source being incident; and a second optical element having an optical characteristic of transmitting the light of the first wavelength, reflecting the light of the second or the third wavelength in a first polarization state and transmitting the light of the second or the third wavelength in a second polarization state, a first surface on which the light reflected by the first optical element is incident, a second surface on which the lights of the second and the third wavelengths from second and third light sources are incident, and a third surface emitting the first, the second and the third lights incident from the first and the second surfaces.

Abstract: An optical pickup includes a light emitting device, a prism, and an objective lens. The light emitting device emits a laser beam. The prism has an entrance face and an exit face. In the prism, the laser beam emitted from the light emitting device is perpendicularly incident on the entrance face, is parallel-shifted, is perpendicularly reflected, and is emerged from the exit face. The objective lens focuses the laser beam emerged from the prism on a recording surface of an optical disk.

Abstract: The present invention discloses an optical system for extracting signal light components from a beam including the signal light components and stray light components. The optical system includes a condensing optical element situated on an optical path of the beam for condensing the beam, a polarization changing unit for changing the state of polarization of at least one of the signal light components and the stray light components included in the incident beam transmitted through the condensing optical element, and an extracting element for extracting the signal light components included in the beam transmitted through the polarization changing unit.

Abstract: An optical pickup device includes: a light source; a collimator lens for converting a light beam emitted from the light source into parallel light; an objective lens for converging the light beam to the optical disc; an extending portion in which a light flux transversal width as the width of the parallel direction with respect to the information recording face of the optical disc of the light beam converted into the parallel light by the collimator lens is extended until a final light flux diameter as the diameter of the light beam at an incident time to the objective lens; and a prism in which a light flux longitudinal width as the width of a direction perpendicular to the information recording face of the optical disc of the extended light beam is extended until the final light flux diameter, and the light beam is emitted to the objective lens.

Abstract: Light emitted from a light source and having a wavelength of 400 nm is reflected by a beam splitter (BS), and converged on a disk according to a next-generation standard. Reflection light therefrom passes through the BS and is received by a photodetector. Light emitted from a light source and having a wavelength of 660 nm is reflected by the BS and passes through the BS, and converged on a disk according to a DVD standard. Reflection light therefrom passes through the BS and is received by the photodetector. About 50% of light emitted from a light source and having a wavelength of 780 nm is reflected by the BS. The light passes through the BS and is then converged on a disk according to a CD standard. Reflection light therefrom passes through the BS. About 50% of the light passes through the BS and is received by the photodetector. Thus, recording and reproduction can be performed on any of disks according to a next-generation standard, DVD standard, and CD standard.

Abstract: An optical pickup apparatus includes a light source emitting a light, an objective lens collecting the light on an optical disk, a collimate lens that is moved in an optical axis direction along a light path of the light to change a divergent angle or a convergent angle of the light, a starting prism that expands a spot shape of an incident light in a first predetermined direction to emit the light, and a beam shaping prism that expands a spot shape of an incident light in a second predetermined direction to emit the light, and the collimate lens, the beam shaping prism, and the starting prism are disposed in order from the light source side toward the objective lens on a light path connecting the light source and the objective lens, and the first predetermined direction is perpendicular to the second predetermined direction. Thereby, it is possible to make an attempt to thin the optical pickup apparatus and an optical disk apparatus using the optical pickup apparatus.

Abstract: An optical pickup device includes a light source, a movable condensing lens, a rising prism or a rising mirror, an objective lens, and a phase plate. The light source emits laser light, and the movable condensing lens converts the laser light into converging light or diverging light. The rising prism or the rising mirror converts an optical axis of laser light passing through the condensing lens into a substantially vertical direction. The objective lens condenses the laser light, of which the optical axis is converted by the rising prism or the rising mirror, to an optical disk. The phase plate is provided between the condensing lens and the objective lens, and includes stepped portions that are formed at portions facing each other and have different thicknesses. The phase plate corrects astigmatism, which is generated by the rising prism or the rising mirror, by making a part of laser light having a size larger than a predetermined size pass through the stepped portions of the phase plate.

Abstract: There is provided an optical head which have no such problems regarding increase in cost and size thereof and can reduce errors by suppressing crosstalk components attributable to reflection on lands of a magneto-optical recording medium and thereby prevent degradation of reproduction characteristics. An optical element includes a light separating section for separating outgoing light and return light, and a phase compensation section for imparting phase compensation to light incident thereon. The optical element is provided on a light path of return light between an objective lens and a photodetector, so as to be closer to the photodetector than the light separating section is. This makes it possible to impart the phase compensation to the return light and prevent the degradation of reproduction characteristics. Light separating elements such as beam splitter are no more necessary in the configuration, with the result that decreases in size and cost can be realized.

Abstract: An optical pickup apparatus includes a plurality of laser light sources, a single objective lens, and a beam shaping mirror. The beam shaping mirror causes each of the laser beams to be incident on a transmission surface, reflects the beam from a reflection surface being unparallel to the transmission surface and causes the beam to emerge from the transmission surface, thereby to convert a light intensity distribution of the beam of each of the wavelengths from an elliptic shape into a circular shape. The beam shaping mirror is made of a liquid crystal, which forms the transmission surface and the reflection surface, and is electrically driven so that a refractive index of the liquid crystal may be held constant irrespective of the wavelengths of the beams each of which enters the beam shaping mirror.

Abstract: There is provided an inexpensive optical pickup device that is capable of accurately detecting light quantities of output laser beams on occasion of at least either of reproduction and recording on an information recording medium. A beam from a first light source 1 which beam does not pass through a wavelength selection film 6 of a light separation element 7 is reflected by a first reflection film 10 in a direction to an optical monitor 5. A beam from a second light source 2 which beam does not pass through the wavelength selection film 6 of the light separation element 7 is reflected by a second reflection film 11 in a direction to the optical monitor 5.

Abstract: A servo controlling method for controlling an information processing apparatus using a hologram. The method includes a step of irradiating a holographic recording medium with light having a first wavelength and irradiating the holographic recording medium with light having a second wavelength, different from the first wavelength, a step of directing first return light by the light of the first wavelength and second return light by the light of the second wavelength to be incident on the same light receiving element, and a step of performing servo control by separating the first return light from the second return light at the light receiving element.

Abstract: The present invention aims to provide an optical head and an optical disk device capable of suitably detecting tracking error signals for different types of optical discs. A polarizing hologram element includes a first area and a second area adjacent to the first area in an area where a beam reflected and diffracted by a BD passes. The first area includes a first transmission area for transmitting many 1st-order diffracted lights from the BD, a second transmission area adjacent to the first transmission area and closer to an optical axis than the first transmission area, and a third transmission area adjacent to the first and second transmission areas. The second area includes a fourth transmission area for transmitting many 1st-order diffracted lights from the BD, a fifth transmission area adjacent to the fourth transmission area and closer to the optical axis than the fourth transmission area, and a sixth transmission area adjacent to the fourth and fifth transmission areas.

Abstract: A near field light generating device generating near field light from incident light by using a solid immersion mirror and a heat assisted magnetic recording head with the same are provided. The near field light generating device includes a light source; a waveguide core which transmits light; and a solid immersion mirror, which generates near field light, including an upper transmission surface through which light from the waveguide core is transmitted into the solid immersion mirror, a lower reflection surface, opposite the upper transmission surface, which reflections light incident thereon, lateral reflection surfaces, facing each other at sides of the solid immersion mirror, which reflect light incident thereon, and a lower transmission region disposed at a center of the lower reflection surface. Light reflected from the lateral reflection surfaces forms a light spot on the lower transmission region.

Abstract: An optical pickup device includes: a laser source for emitting, to an optical disk, a laser beam having a wavelength ?1 and a laser beam having a wavelength ?2, which is longer than the wavelength ?1; a light receiver, for receiving laser beams that are reflected by the optical disk; a beam splitter, for directing, to the light receiver, the laser beams reflected by the optical disk; and an astigmatism generation element, located between the beam splitter and the light receiver, for generating the laser beams to be used for focusing control, by designating as the front of the light receiver a focal point on one of the intersecting cross sections that include the light axes of the laser beams, and by designating as the rear of the light receiver, a focal point on the other cross section, wherein the astigmatism generation element is an optical element, which is like a Fresnel lens, whose step depth is substantially a natural number times either the wavelength ?1 or the wavelength ?2.

Abstract: A reading device for holographic storage includes a light source, a light-directing component, an optical sensor and a prism. The light-directing component is disposed on the transmission path of the light beam provided by the light source and directs the light beam to get incidence at a holographic storage medium in a reading angle to generate a data beam. The optical sensor is suitable for reading the data beam and reproducing stored data. The prism is disposed between the light source and the holographic storage medium and rotatable about a rotation axis perpendicular to the transmission path of the light beam for fine-adjusting the reading angle. The prism and the light beam satisfy the following formula: ?{square root over (n2?sin2I1)}×sin A?cos A sin I1<1 I1 is the angle of incidence of the light beam, A is the vertex angle between the light incident surface and the light emerging surface and n is the refractive index of the prism.

Abstract: An optical unit includes: a first light emitting device configured to emit a first beam; and a second light emitting device configured to emit a second beam in a direction the same as a direction of the first beam where the second beam is different in wavelength from the first beam. An emission surface of the second light emitting device is arranged at a distance from an emission surface of the first light emitting device in an opposite direction to the direction of the first beam.

Abstract: A polarizing beam splitter for separating an upstream beam from a downstream beam according to the polarization of an incident beam is provided between first and second light sources emitting laser beams at respective wavelength and an objective lens. A phase plate for providing a phase difference to a beam incident on the polarizing beam splitter is provided between the polarizing beam splitter and the light sources. A portion of the laser beam incident on the polarizing beam splitter is reflected by the polarizing beam splitter and caused to be incident on a photo-detecting unit, so as to prevent an unnecessary portion of the laser beam is incident on the photo-detecting unit. According to the invention, the laser beam is used efficiently and the cost of fabricating an optical disk apparatus is reduced by eliminating a need for a gain controlling circuit in the photo-detecting unit.

Abstract: A method for fabricating a prism that comprises a first and a second substrate, both translucent, bonded together with an optical thin film interposed at the interface in between and that is used with the interface inclined relative to the optical axis of incident laser light of a wavelength of 420 nm or shorter includes the step of bonding together the first and second substrates of which the difference ?N1 in refractive index at the wavelength of the laser light fulfills the condition: ?N1?|1/(0.3×104×NA×t)|, where t represents the thickness of the first and second substrates cemented together as measured along the optical axis of the laser light, and NA represents the numerical aperture of the incident laser light.

Abstract: The present invention relates to an optical device which includes a first laser diode, a beam splitter, a first objective lens, a photo-detector, a second laser diode, a wedged plate beam splitter, a second objective lens and a collimator. The present invention deploys two independent transmitting paths. The retrieving paths share the beam splitter and the photo-detector commonly at the returning route.