Abstract: A fiber laser device contains a first optical fiber of a double-clad type in which optical resonance of an infrared laser light takes place inside a core with Pr3+and Yb3+added thereto to generate a light of a wavelength of about 630 nm, a second optical fiber of a double-clad type in which optical resonance of an infrared laser light takes place inside a core with Pr3+and Yb3+added thereto to generate a light of a wavelength of about 690 nm, and a third optical fiber in which optical resonance of the lights from the first and second optical fibers takes place inside a core with Tm3+added thereto to generate a light of a wavelength of about 450 nm, and the core diameter of the third optical fiber is made substantially equal to the spot diameters of the lights from the first and second optical fibers.

Abstract: A laser apparatus according to this invention includes an optical resonator, which has a mirror capable of enclosing light with a required output wavelength and light with a first non-required output wavelength able to increase the efficiency of generating the light with the required output wavelength, in an optical fiber, at both ends of an optical fiber added with ions capable of generating light with a required output wavelength, and damping or discharging light with a second non-required output wavelength to suppress generation of light with the required output wavelength, to outside.

Abstract: The present invention relates to a laser output device in which laser light of a specific wavelength transmitted in an optical fiber is returned to the optical fiber by means of a mirror so that high output laser light can be emitted. The device is equipped with an optical fiber, a mirror configured to reflect light of the specific wavelength transmitting in the optical fiber to return the light to the optical fiber, and a support portion configured to support an end surface of the optical fiber and the mirror in a state in which they are pressed against each other.

Abstract: A fiber laser apparatus, an image display apparatus and an excitation method for an up-conversion fiber laser apparatus are disclosed. A polarizer and a high-reflection mirror for retrieving an up-conversion laser output are interposed between an exciting laser for emitting an exciting laser beam and a rare-earth-doped fiber. That portion of the exciting laser beam output from the output side of the rare-earth-doped fiber which has a polarized wave directed at right angles to the polarized wave incident on the rare-earth-doped fiber is returned into the rare-earth-doped fiber. The exciting laser beam having the other polarized wave is output in a direction different from the direction of the exciting laser.

Abstract: Rays of light emitted from the semiconductor laser are converted into parallel rays of light by cylindrical lenses. Then, the light passed through the cylindrical lenses is caused to enter an optical fiber changed continuously from a specific position in the middle toward an incidence end part in such a manner that the core shape at the incidence end part becomes elliptic, with the cross-sectional area remaining unchanged.

Abstract: A fiber laser apparatus comprises a plurality of semiconductor lasers, and an optical fiber which beams emitted from the plurality of semiconductor lasers are caused to enter. The plurality of semiconductor lasers being so arranged that the emitted beams are almost parallel to one another in a slow-axis direction and the incidence angles of the emitted beams to the optical fiber differ from one another in a fast-axis direction.

Abstract: A light-transmissible plate having the function of shielding electromagnetic waves includes a transparent plastic base plate, a hard coating layer on the base plate, an electroconductive layer on the hard coating layer and a layer having low refractive index on the electroconductive layer. The plate can shield electromagnetic waves, and can have high damage resistance even if the plastic constituting the base plate has low surface hardness. Moreover, it is possible to give the plate the ability to prevent reflection. A light-transmissible plate according to a second embodiment of the present invention includes an anti-reflection film composed of a plurality of layers on a surface opposite to the surface on which the electroconductive layer is provided.