Abstract: A waveguide is provided, in which the optical coupling efficiency to a light source is sufficiently high, and the light-emitting spot center is stably provided at the intended position. The waveguide comprises a multilayered structure in which refractive indexes of layers having a surface contact with each other are different from each other. The multilayered structure is divided into a plurality of groups, and the length from the light-receiving end surface to the light-emitting end surface of one group is different from that of the neighboring group, and the protruded light-emitting end surface of the first group defined as a group that has the largest length includes a center of the light-emitting spot. In this waveguide, the state in which the light-emitting spot center is positioned within the light-emitting end surface does not easily be changed, even when the light-receiving spot center within the light-receiving end surface is rather displaced.

Abstract: The present invention provides a two-dimensional photonic crystal in which an absolute photonic band gap (PBG), i.e. a photonic band gap that is effective for both the TE-polarized light and the TM-polarized light within a predetermined wavelength range, is created with an adequate bandwidth. The body 21 is provided with holes 22 arranged in a triangular lattice pattern, where the basic shape of the hole is an equilateral triangle. This shaping and arranging of the holes creates an absolute PBG. Each corner of the equilateral triangle is cut along an arc to leave an adequate distance between the neighboring holes (i.e. an adequate width of the connecting portion of the body). This design makes it possible to enlarge each hole 22 while ensuring an adequate strength of the two-dimensional photonic crystal. This construction creates an absolute PBG having a large width.

Abstract: A magnetic recording head capable of a satisfying thermally-assisted magnetic recording without depending on the use of a near-field light generator is provided. The head comprises a waveguide and a main magnetic pole having a main pole tip. Further, at least a portion of the main pole tip is embedded in a groove provided in the upper surface of the waveguide. Further, a second clad layer is provided on the first clad layer and on a rear side from the main pole tip. This configuration of the first and second clad layers suppresses the absorption of the light propagating through the waveguide by the main magnetic pole. Further, the configuration in which at least a portion of the main pole tip is embedded in the groove can cause the distance between the light spot center of the waveguide and the main magnetic pole to be sufficiently small.

Abstract: A near-field light generating device includes: a waveguide having a groove that opens in the top surface; a clad layer disposed on the top surface of the waveguide and having an opening that is contiguous to the groove; a near-field light generating element accommodated in the opening; and a buffer layer interposed between the near-field light generating element and each of the waveguide and the clad layer in the groove and the opening. The near-field light generating element includes: first and second side surfaces that decrease in distance from each other toward the groove; an edge part that connects the first and second side surfaces to each other and is opposed to the groove with the buffer layer therebetween; and a near-field light generating part that lies at one end of the edge part and generates near-field light.

Abstract: A planar plasmon antenna is formed on a YZ plane including a Z-axis, the Z-axis being a propagation direction of excitation light for near-field light generation. The longitudinal direction of the planar plasmon antenna is oblique relative to the Y-axis, and the angle of a corner of the planar plasmon antenna in the YZ plane is an acute angle. The corner, which forms an acute angle, generates intense near-field light in response to excitation light irradiation.

Abstract: Provided is a plasmon antenna in which a near-field light having a sufficient intensity is generated only in a desired location. The plasmon antenna comprises an end surface on a side where a near-field light is generated; the end surface is flat and has a shape with at least three vertexes or rounded corners; and an end surface of the plasmon antenna which is opposite to the flat end surface and receives light, is inclined with respect to the flat end surface so as to become closer to the flat end surface toward one of the at least three vertexes or rounded corners. When the light-receiving end surface of the plasmon antenna is irradiated with the light, a near-field light having a sufficient intensity can be generated at only the vertex or rounded corner toward which the entire plasmon antenna becomes thinner.

Abstract: A thermally assisted magnetic head according to the present invention includes: a medium-facing surface, a main magnetic pole provided on the medium-facing surface, and a plasmon antenna provided on the medium-facing surface in the vicinity of the main magnetic pole, wherein the plasmon antenna is shaped as a triangular flat plate having first, second and third corners, such that the distance from the first corner to the main magnetic pole is shorter than the distance from the second corner to the main magnetic pole and the distance from the third corner to the main magnetic pole, and the interior angle ? of the first corner, the interior angle ? of the second corner and the interior angle ? of the third corner satisfy relationships ?<?, ?<? and ???.

Abstract: A head capable of favorite thermally-assisted magnetic recording without depending on the use of a near-field light generator is provided. The head comprises a write head element formed on the trailing side from a waveguide and comprising a first main pole. The first main pole and the waveguide are opposed to each other through a first clad layer, and a second clad layer is provided on a rear side from the first main pole. This gives that the end surface of the waveguide can be placed much close to the end surface of the first main pole apart by only a thickness of the first clad layer. As a result, the end surface of the first main pole can apply a sufficient intensity of write field to the intensity center and its vicinity of the light spot formed on the magnetic recording layer.

Abstract: The present invention provides a polarized light mode converter which can be provided within a two-dimensional photonic crystal or can be smoothly connected to a two-dimensional photonic crystal. In a two-dimensional photonic crystal made of a slab-like main body provided with a plurality of different refractive index regions (for example, holes 22) arranged in a lattice in the main body, where the different refractive index regions have a refractive index different from that of the main body, a polarized light conversion waveguide 23 is formed which is comprised of defects of the different refractive index regions arranged linearly whose a cross-sectional shape is asymmetrical in a vertical and in a horizontal direction. The polarized light conversion waveguide 23 can be, for example, realized by providing, on a side of the waveguide, holes 221 and 222 extending in a direction oblique to a the main body surface.

Abstract: A near-field light generating device includes: a base having a top surface; a waveguide that allows laser light to propagate therethrough and is disposed above the top surface of the base; and a surface plasmon generating element that is disposed above the top surface of the base so as to adjoin the waveguide in a direction parallel to the top surface of the base. The waveguide has a side surface that faces the surface plasmon generating element. The surface plasmon generating element includes: a coupling part that is opposed to a part of the side surface of the waveguide with spacing therebetween and causes excitation of a surface plasmon by coupling with evanescent light occurring from the part of the side surface; and a near-field light generating part that generates near-field light based on the surface plasmon excited at the coupling part.

Abstract: A thermally assisted magnetic head includes a slider having a medium-facing surface and a surface-emitting semiconductor laser. The slider has a slider substrate on which part of the medium-facing surface is formed, and a magnetic head portion, on which another part of the medium-facing surface is formed, and which has a first surface in contact with a head stacking surface of the slider substrate, a second surface opposite the first surface, and a third surface opposite the medium-facing surface. The magnetic head portion comprises a main magnetic pole, an optical waveguide core having a first light exit surface at the medium-facing surface and a second light exit surface at the third surface, a first diffraction grating, provided in the optical waveguide core or further towards the second surface than the optical waveguide core, and a light reflective section provided further toward the first surface than the optical waveguide core.

Abstract: A thermally assisted magnetic head includes: a slider having a medium-facing surface; and a surface-emitting semiconductor laser. The slider has: a slider substrate, on which part of the medium-facing surface is formed; and a magnetic head portion, on which another part of the medium-facing surface is formed, and which has a first surface in contact with a head stacking surface of the slider substrate and a second surface opposite the first surface. The magnetic head portion has: a main magnetic pole that generates a write magnetic field from an end face on the side of the medium-facing surface; an optical waveguide core extending along the first surface and having a light exit surface at the medium-facing surface; and a diffraction grating, which is provided in the optical waveguide core or further towards the second surface than the optical waveguide core, and the refractive index of which varies periodically along the direction in which the optical waveguide core extends.

Abstract: The present thermally assisted magnetic head has: a plasmon antenna; an optical wave guide having the plasmon antenna installed at the tip thereof; a diffraction grating which is disposed in or on the optical wave guide; and a laser element which is disposed at a position to irradiate laser beams onto the diffraction grating, and is composed of a photonic crystal surface emitting semiconductor layer. A laser light intensity distribution on the diffraction grating has at least two intensity peaks in the width direction of the optical wave guide. The two-dimensional form of the laser light intensity distribution on the diffraction grating is a ring or two ellipses.

Abstract: Foundation layers of a thin film magnetic head are disposed between insulating layers and bias magnetic field application layers, and are configured of Cr or Cr alloy. The insulating layers are configured of a Si oxide such that the Si content of the Si oxide is in the range of 30˜56 at % (atom %) and that the atom ratio of oxygen to Si (O/Si) is in the range of 0.8˜1.3. With the configuration, the occurrence rate of noise is reduced.

Abstract: The present invention has been made for providing a photonic crystal capable of multiplexing or demultiplexing light within a wavelength band having a certain width. It includes a slab-shaped body 21 provided with plural forbidden band zones 211 and 212, and holes 221 and 222 having different sizes are arranged in the forbidden band zones with different cycles, respectively. Also formed are a trunk waveguide 24 extending along the direction inclined by +30 degrees from a perpendicular of the boundary 23 between the forbidden band zones 211 and 212, and a branch waveguide 25 extending along the direction inclined by ?30 degrees.

Abstract: Provided is a method for forming a near-field light generating element, which is capable of sufficiently suppressing the unevenness of a waveguide surface and the distortion within the waveguide. The forming method comprises the steps of: forming a first etching stopper layer on a lower waveguide layer; forming a second etching stopper layer; forming, on the second etching stopper layer, a plasmon antenna material layer; performing etching with the second etching stopper layer used as a stopper, to form a first side surface of plasmon antenna; forming a side-surface protecting mask so as to cover the first side surface; and performing etching with the first and second etching stopper layers used as stoppers, to form the second side surface. By providing the first and second etching stopper layer, over-etching can be prevented even when each etching process takes enough etch time, which allows easy management of etching endpoints.

Abstract: The thermally assisted magnetic head according to the present invention comprises a medium-facing surface, a main magnetic pole provided on the medium-facing surface, and a plasmon antenna provided on the medium-facing surface, in the vicinity of the main magnetic pole. The shape of the plasmon antenna, as viewed from a direction perpendicular to the medium-facing surface, is a triangle having first, second and third corners, the plasmon antenna being shaped as a flat plate the thickness direction of which is perpendicular to the medium-facing surface. The distance from the first corner to the main magnetic pole is shorter than the distance from the second corner to the main magnetic pole and the distance from the third corner to the main magnetic pole. The second corner and the third corner are rounded.

Abstract: The present invention intends to provide a two-dimensional photonic crystal having a wide photonic band gap (PBG). In a slab-shaped body 31, a number of holes 32, whose sectional shape on a plane parallel to the slab surface is an equilateral triangle, are periodically arranged in a triangular lattice pattern. The upper and lower sides of the holes 32 are covered with the material of the body 31. The aforementioned sectional shape is uneven along the direction perpendicular to the slab surface. This construction expands the PBG for TM-polarized light and thereby increases its energy region overlapping with the PBG for TE-polarized light. This overlapping section is the complete PBG. If a ray of light whose wavelength corresponds to an energy level within the complete PBG, neither the TE-polarized nor TM-polarized component of the light can be propagated through the photonic crystal.

Abstract: Provided is a surface plasmon antenna that can be set so that the emitting position on the end surface of the plasmon antenna where near-field light is emitted is located sufficiently close to the end of a magnetic pole. The surface plasmon antenna comprises an edge having a portion for coupling with a light in a surface plasmon mode. The edge is provided for propagating surface plasmon excited by the light and extends from the portion to a near-field light generating end surface that emits near-field light. The edge for propagating surface plasmon is a very narrow propagation region. Therefore, the near-field light generating end surface, which appears as a polished surface processed through polishing in the manufacturing of the plasmon antenna, can be made a shape with a very small size, and further can be set so that surface plasmon propagates to reach the end surface reliably.

Abstract: Provided is a plasmon antenna in which a near-field light having a sufficient intensity is generated only in a desired location. The plasmon antenna comprises an end surface on a side where a near-field light is generated; the end surface is flat and has a shape with at least three vertexes or rounded corners; and an end surface of the plasmon antenna which is opposite to the flat end surface and receives light, is inclined with respect to the flat end surface so as to become closer to the flat end surface toward one of the at least three vertexes or rounded corners. When the light-receiving end surface of the plasmon antenna is irradiated with the light, a near-field light having a sufficient intensity can be generated at only the vertex or rounded corner toward which the entire plasmon antenna becomes thinner.