Abstract: An image forming apparatus configured to form an image on a recording material includes a detection unit configured to detect a temperature of a first member, and an estimation unit configured to estimate a temperature of a second member, which is different from the first member. The estimation unit is configured to estimate, based on the temperature of the second member estimated by the estimation unit at a first timing, which is a timing before the image forming apparatus is powered off, the temperature of the first member detected by the detection unit at a second timing, which is a timing after the image forming apparatus is powered on, and information representing an operation history of the image forming apparatus until when the image forming apparatus is powered off, the temperature of the second member at the second timing.

Abstract: In a motor control apparatus, an exciting unit excites a plurality of excitation phases of a motor. A current measurement unit measures exciting currents flowing through coils of respective phases of the motor, and generates measurement data including measurement values of the exciting currents. A determination unit determines whether or not noise is superimposed on a measurement value included in the measurement data by comparing, with respect to each of the plurality of excitation phases, the measurement data regarding a first phase coil that constitutes that excitation phase with the measurement data regarding a second phase coil that constitutes that excitation phase.

Abstract: In a motor control apparatus, an exciting unit excites a plurality of excitation phases of a motor. A current measurement unit measures exciting currents flowing through coils of respective phases of the motor, and generates measurement data including measurement values of the exciting currents. A determination unit determines whether or not noise is superimposed on a measurement value included in the measurement data by comparing, with respect to each of the plurality of excitation phases, the measurement data regarding a first phase coil that constitutes that excitation phase with the measurement data regarding a second phase coil that constitutes that excitation phase.

Abstract: An optical-coherence-tomography apparatus includes a light-source unit configured to emit light while changing a wavelength of the light; an optical interferometric system configured to split the light from the light-source unit into illuminating light to be applied to an object and reference light, and to generate interfering light from the illuminating light reflected by the object and the reference light; a photodetection unit configured to receive the interfering light, and an information-acquiring unit configured to acquire information on the object from the interfering light received by the photodetection unit. The light-source unit performs wavelength sweep by displacing a movable portion with an electrostatic force generated with the application of a voltage. The optical-coherence-tomography apparatus further includes a pull-in-detection unit configured to detect whether or not a pull-in effect is occurring on the movable portion of the light-source unit.

Abstract: An optical-coherence-tomography apparatus includes a light-source unit configured to emit light while changing a wavelength of the light; an optical interferometric system configured to split the light from the light-source unit into illuminating light to be applied to an object and reference light, and to generate interfering light from the illuminating light reflected by the object and the reference light; a photodetection unit configured to receive the interfering light, and an information-acquiring unit configured to acquire information on the object from the interfering light received by the photodetection unit. The light-source unit performs wavelength sweep by displacing a movable portion with an electrostatic force generated with the application of a voltage. The optical-coherence-tomography apparatus further includes a pull-in-detection unit configured to detect whether or not a pull-in effect is occurring on the movable portion of the light-source unit.

Abstract: A method of calibrating an optical frequency of light emitted from a wavelength-swept light source thereby allowing it to compensate for an error of a wavelength includes performing a first process of measuring an optical frequency range of the emitted light while changing a control parameter associated with an optical frequency sweeping mechanism and determining a correspondence between the control parameter and the optical frequency range, performing a second process of measuring a maximum of a gain of an active medium included in the wavelength-swept light source and determining a correspondence between the maximum of the gain and the control parameter, performing a third process of determining a relationship between the optical frequency range of the emitted light and the control parameter corresponding to the maximum gain of the active medium, and performing a fourth process of adjusting the control parameter based on the determined relationship.

Abstract: A surface emitting laser includes an active layer; a periodic-structure layer including a low-refractive-index medium and a high-refractive-index medium and whose refractive index varies periodically, the periodic-structure layer being provided at a position where light emitted from the active layer couples therewith; and a pair of electrodes from which electricity is supplied to the active layer. The periodic-structure layer is patterned as a square periodic-structure lattice. At least one of the electrodes includes one or more linear electrodes. A direction of each lattice vector of the periodic structure and a longitudinal direction of the linear electrodes are different from each other.

Abstract: A vertical cavity surface emitting laser includes a cavity formed by a pair of reflectors on a substrate and an active region interposed in the cavity. In the vertical cavity surface emitting laser, at least one of the reflectors that form the cavity has a refractive index periodic structure produced by arranging a first medium and a second medium so as to make the refractive index change periodically in in-plane directions of the substrate and the cross sectional area of the first medium in the in-plane directions changes in the direction of the thickness of the first medium. The vertical cavity surface emitting laser has reflectors having a wide reflection band.

Abstract: A surface emitting laser which oscillates at a wavelength ? of a blue band, including a photonic crystal layer including a photonic crystal structure, an active layer provided on one surface of the photonic crystal layer, and an electrode provided on the other surface of the photonic crystal layer for injecting electric current into the active layer. The photonic crystal structure has a thickness of 100 nm or more. A laser beam is emitted toward a direction opposite to a side of the photonic crystal layer on which the electrode is provided.

Abstract: A vertical cavity surface emitting laser is provided which controls the reflectivity at the middle portion and the peripheral portion of the mirror with a simple structure to cause oscillation of a single lateral mode by use of a mirror having the refractive index changing periodically in the mirror plane direction. The vertical cavity surface emitting laser.

Abstract: A vertical cavity surface emitting laser device includes a first reflective mirror layer, a second reflective mirror layer, and an active layer disposed therebetween, wherein at least one of the first reflective mirror layer and the second reflective mirror layer includes a periodic-refractive-index structure in which the refractive index periodically changes in the in-plane direction and a part of the periodic-refractive-index structure includes a plurality of parts that disorder the periodicity.

Abstract: To provide a structure having a photonic crystal that can display a reflection function using GR even when a refractive index difference between a photonic crystal layer and a cladding layer adjacent thereto is not sufficient and a surface-emitting laser using the structure. The structure includes a photonic crystal layer including a first member of a flat shape and plural pillars arrayed two-dimensionally periodically on the first member. The photonic crystal layer is formed of a first material having a first refractive index. A low refractive index layer formed of a second material having a second refractive index lower than the first refractive index is adjacent to the photonic crystal layer. A relative refractive index difference between the first refractive index and the second refractive index is not less than 0.04 and does not exceed 0.13. The height of the pillars with respect to the thickness of the photonic crystal layer is not less than 0.10t and does not exceed 0.07t.

Abstract: A surface emitting laser device can further improve the light emission efficiency thereof to enlarge the degree of freedom of the device. The surface emitting laser device includes an active layer 103, a photonic crystal layer disposed to be adjacent to the active layer, an electrode 108 disposed on the photonic crystal layer, and a plurality of light emitting regions regulated by the electrode. The photonic crystal layer is configured to include a first photonic crystal region 104 disposed just under the electrode, and having a periodic refractive index structure for resonance of light within a plane, and a second photonic crystal region 105 disposed just under the light emitting region, and having a periodic refractive index structure for emitting light in a direction perpendicular to the plane.

Abstract: A surface emitting laser device can further improve the light emission efficiency thereof to enlarge the degree of freedom of the device. The surface emitting laser device includes an active layer 103, a photonic crystal layer disposed to be adjacent to the active layer, an electrode 108 disposed on the photonic crystal layer, and a plurality of light emitting regions regulated by the electrode. The photonic crystal layer is configured to include a first photonic crystal region 104 disposed just under the electrode, and having a periodic refractive index structure for resonance of light within a plane, and a second photonic crystal region 105 disposed just under the light emitting region, and having a periodic refractive index structure for emitting light in a direction perpendicular to the plane.

Abstract: A surface emitting laser which oscillates at a wavelength X of a blue band, including a photonic crystal layer including a photonic crystal structure, an active layer provided on one surface of the photonic crystal layer, and an electrode provided on the other surface of the photonic crystal layer for injecting electric current into the active layer. The photonic crystal structure has a thickness of 100 nm or more. A laser beam is emitted toward a direction opposite to a side of the photonic crystal layer on which the electrode is provided.

Abstract: A vertical cavity surface emitting laser is provided which controls the reflectivity at the middle portion and the peripheral portion of the mirror with a simple structure to cause oscillation of a single lateral mode by use of a mirror having the refractive index changing periodically in the mirror plane direction. The vertical cavity surface emitting laser.

Abstract: A structure includes a photonic crystal layer including a first member having a high refractive index in which a plurality of holes are periodically arranged, and a second member having a low refractive index. A third member is disposed on the first member. The third member has a refractive index higher than 1.0 and lower than the refractive index of the first member. The holes of the photonic crystal layer have a depth in the range of 20% to 80% of the thickness of the first member.

Abstract: To provide a light-emitting device having a resonator capable of stably and efficiently taking out light. The device includes an active medium, a resonator for confining the light having a first wavelength emitted from the active medium within a three-dimensional space and a wavelength conversion medium for converting the wavelength of the light having the first wavelength into a second wavelength.

Abstract: A vertical cavity surface emitting laser device includes a first reflective mirror layer, a second reflective mirror layer, and an active layer disposed therebetween, wherein at least one of the first reflective mirror layer and the second reflective mirror layer includes a periodic-refractive-index structure in which the refractive index periodically changes in the in-plane direction and a part of the periodic-refractive-index structure includes a plurality of parts that disorder the periodicity.

Abstract: A vertical cavity surface emitting laser device includes a first reflective mirror layer, a second reflective mirror layer, and an active layer disposed therebetween, wherein at least one of the first reflective mirror layer and the second reflective mirror layer includes a periodic-refractive-index structure in which the refractive index periodically changes in the in-plane direction and a part of the periodic-refractive-index structure includes a plurality of parts that disorder the periodicity.