Abstract: A photonic crystal laser capable of producing a radially-polarized halo-shaped laser beam having a smaller width than conventional beams includes: an active layer; a ring-shaped photonic crystal including a plate-shaped base body on one side of the active layer, the base body having a number of modified refractive index areas of the same shape, the modified refractive index areas having a refractive index different from the base body and periodically arranged in the circumferential direction of a ring, and each of the modified refractive index areas being asymmetrically shaped with respect to an axis extending through the center of the modified refractive index area in the radial direction of the ring; a first and second electrode facing each other across the active layer and the ring-shaped photonic crystal; and a window provided in the second electrode capable of allowing passage of a laser light generated from the ring-shaped photonic crystal.

Abstract: A photonic crystal laser capable of producing a radially-polarized halo-shaped laser beam having a smaller width than conventional beams includes: an active layer; a ring-shaped photonic crystal including a plate-shaped base body on one side of the active layer, the base body having a number of modified refractive index areas of the same shape, the modified refractive index areas having a refractive index different from the base body and periodically arranged in the circumferential direction of a ring, and each of the modified refractive index areas being asymmetrically shaped with respect to an axis extending through the center of the modified refractive index area in the radial direction of the ring; a first and second electrode facing each other across the active layer and the ring-shaped photonic crystal; and a window provided in the second electrode capable of allowing passage of a laser light generated from the ring-shaped photonic crystal.

Abstract: A two-dimensional photonic crystal laser light is provided. The two-dimensional photonic crystal laser includes a two-dimensional photonic crystal made of a plate-shaped member provided with a periodic arrangement of identically-shaped modified refractive index areas having a refractive index different from that of the plate-shaped member; and an active layer provided on one side of the two-dimensional photonic crystal. The modified refractive index areas are arranged at lattice points of a lattice with a same period at least in two directions; each modified refractive index area is shaped so that a feedback strength is different with respect to directions of two primitive lattice vectors of the lattice; the two-dimensional photonic crystal has a periodic structure of a supercell, which contains a plurality of lattice points; and the sum of the feedback strengths by all modified refractive index areas in the supercell is identical in each direction of the two primitive lattice vectors.

Abstract: A laser capable of emitting multiple laser beams is provided. A two-dimensional photonic crystal laser according to the present invention has a laminated structure including an active layer, a first photonic crystal layer having a periodic distribution of refractive index with a first period, and a second photonic crystal layer having a periodic distribution of refractive index with a second period that differs from the first period. This two-dimensional photonic crystal laser can emit a main beam traveling in a direction perpendicular to the two-dimensional photonic crystals and side beams each traveling in a direction inclined with respect to the main beam. These beams can be used, for example, in a recording/reproducing device by means of an optical disk, the main beam being used for recording/reproducing information and the side beams for following up the track.

Abstract: A two-dimensional photonic crystal laser light is provided. The two-dimensional photonic crystal laser includes a two-dimensional photonic crystal made of a plate-shaped member provided with a periodic arrangement of identically-shaped modified refractive index areas having a refractive index different from that of the plate-shaped member; and an active layer provided on one side of the two-dimensional photonic crystal. The modified refractive index areas are arranged at lattice points of a lattice with a same period at least in two directions; each modified refractive index area is shaped so that a feedback strength is different with respect to directions of two primitive lattice vectors of the lattice; the two-dimensional photonic crystal has a periodic structure of a supercell, which contains a plurality of lattice points; and the sum of the feedback strengths by all modified refractive index areas in the supercell is identical in each direction of the two primitive lattice vectors.

Abstract: An objective of the present invention is to provide a surface emitting laser capable of selectively generating a laser oscillation in the fundamental mode and thereby emitting a single-wavelength laser light. In a surface emitting laser including an active layer and a two-dimensional photonic crystal provided on one side of the active layer, a reflector 45 or 46 is provided at least at a portion of the circumference of the two-dimensional photonic crystal. The reflector has a reflectance distribution in which the reflectance has a maximum value at a position where the amplitude envelope of the fundamental mode of an internal resonance light created within the two-dimensional photonic crystal. This design strengthens the fundamental mode while suppressing the second mode, thus enabling the laser oscillation in the fundamental mode to be selectively obtained, so that a single-wavelength laser light can be emitted.

Abstract: The two-dimensional photonic crystal surface emitting laser according to the present invention includes a number of main modified refractive index areas periodically provided in a two-dimensional photonic crystal and secondary structures each relatively located in a similar manner to each of the main modified refractive index areas. The location of the secondary structure is determined so that a main reflected light which is reflected by a main modified refractive index area and a secondary reflected light which is reflected by a secondary structure are weakened or intensified by interference.

Abstract: An objective of the present invention is to provide a surface emitting laser capable of selectively generating a laser oscillation in the fundamental mode and thereby emitting a single-wavelength laser light. In a surface emitting laser including an active layer and a two-dimensional photonic crystal provided on one side of the active layer, a reflector 45 or 46 is provided at least at a portion of the circumference of the two-dimensional photonic crystal. The reflector has a reflectance distribution in which the reflectance has a maximum value at a position where the amplitude envelope of the fundamental mode of an internal resonance light created within the two-dimensional photonic crystal. This design strengthens the fundamental mode while suppressing the second mode, thus enabling the laser oscillation in the fundamental mode to be selectively obtained, so that a single-wavelength laser light can be emitted.

Abstract: An objective of the present invention is to provide a laser capable of producing a radially polarized laser beam with an annular cross section. A laser oscillator 60 including an active layer 53 and two-dimensional photonic crystal 55 with circular holes 552 arranged in a square lattice pattern is provided between two electrodes 571 and 572. A first polarization control layer 581, which functions as a half-wave plate, and a second polarization control layer 582, which functions as a half-wave plate with a fast axis 592 extending at an angle of 45° to that of the first polarization control layer 581, are located on the laser oscillator 60. When a voltage is applied between the electrodes, a circumferentially polarized annular laser beam is emitted from the laser oscillator 60. When passing through the first polarization control layer 581 and the second polarization control layer 582, the laser beam is converted to a radially polarized beam.

Abstract: A laser capable of emitting multiple laser beams is provided. A two-dimensional photonic crystal laser according to the present invention has a laminated structure including an active layer, a first photonic crystal layer having a periodic distribution of refractive index with a first period, and a second photonic crystal layer having a periodic distribution of refractive index with a second period that differs from the first period. This two-dimensional photonic crystal laser can emit a main beam traveling in a direction perpendicular to the two-dimensional photonic crystals and side beams each traveling in a direction inclined with respect to the main beam. These beams can be used, for example, in a recording/reproducing device by means of an optical disk, the main beam being used for recording/reproducing information and the side beams for following up the track.

Abstract: The two-dimensional photonic crystal surface emitting laser according to the present invention includes a number of main modified refractive index areas periodically provided in a two-dimensional photonic crystal and secondary structures each relatively located in a similar manner to each of the main modified refractive index areas. The location of the secondary structure is determined so that a main reflected light which is reflected by a main modified refractive index area and a secondary reflected light which is reflected by a secondary structure are weakened or intensified by interference.

Abstract: A surface-emitting laser according to the present invention includes a laminated body between a first electrode 471 and a second electrode 472. The laminated body includes an active layer 43 and a two-dimensional photonic crystal 45. The first electrode 471 is ring shaped. A voltage is applied between the first and second electrodes 471 and 472 to supply an electric current into the active layer 43 and thereby cause an emission of light. Since the first electrode 471 is ring shaped, the light thereby generated has a ring-shaped field distribution within the two-dimensional photonic crystal 45. Due to this field distribution, a radially polarized laser beam having a ring-shaped cross section is emitted from the two-dimensional photonic crystal 45. The laser beam thus generated can be focused by a focusing lens to make its diameter smaller than the diffraction limit. Such a laser beam is suitable for optical pickups and other optical devices.