Abstract: A laser apparatus includes a resonator and an excitation source as gain section excitation means. The resonator includes a gain section in which population inversion is obtained by optical excitation or current injection, non-gain sections in which gain with respect to a laser oscillating light beam is not positive, and two reflection mirrors. The gain section has an optical path length approximately one half that of the resonator and placed at the central portion with respect to the optical axis of the resonator. The non-gain sections are arranged on both sides of the gain section. The two reflection mirrors are arranged further outside of the non-gain sections.

Abstract: The collected lumber of the present invention is formed by heating and softening a plurality of woods, applying adhesive on the woods, pressing and compressing the wood with adhesive thereon to mold the integral body in a prescribed shape, and by fixation treating the integral body using a heating device. The method for manufacturing collected lumber of this invention comprises the first process for softening woods by heat treating a plurality of woods, the second process for applying adhesive on the softened woods, the third process for forming integral body by pressing and compressing the woods applied with the adhesive to mold in a prescribed shape, and the fourth process for fixation treating the integral body using a heating device.

Abstract: The invention relates to an optical computing element for use in an optical computer utilizing computing light rays having a plurality of wavelength components. The optical computing element comprises a photo-chemical hole burning element which functions as a wavelength selecting filter of the computing light rays. Therefore, the optical computer using the photo-chemical hole burning element of the invention can perform arithmetic operations by taking advantage of differences in optical wavelength. The computer can efficiently perform bulky arithmetic processing, and can also speedily perform arithmetic operations through simultaneous parallel processing for information.

Abstract: The invention relates to an optical computing element for use in an optical computer utilizing computing light rays having a plurality of wavelength components. The optical computing element comprises a photo-chemical hole burning element which functions as a wavelength selecting filter of the computing light rays. Therefore, the optical computer using the photo-chemical hole burning element of the invention can perform arithmetic operations by taking advantage of differences in optical wavelength. The computer can efficiently perform bulky arithmetic processing, and can also speedily perform arithmetic operations through simultaneous parallel processing for information.

Abstract: In an optical recording medium, 4,8-diamino-2-(4-hexyloxyphenyl)-1,5-dihydroxyanthraquinone is used as guest molecules, for an optical recording layer, and a compound expressed by a general formula (1): ##STR1## (where R.sub.1 denotes H or CH.sub.3, R.sub.2 denotes C.sub.2 H.sub.4, C.sub.3 H.sub.6 or C.sub.4 H.sub.8, and n denotes an integer) is used for the host molecules. Since holes are caused in the wavelength region of the semiconductor laser, optical recording can be performed efficiently by using a semiconductor laser.

Abstract: A frequency multiple outgoing light is obtained by intensity-modulating a frequency multiple incident light in frequency domain, after irradiating a pump beam to an optical recording medium consisting of photochromic material and the like to generate optical Stark effect thereon and shifting the light absorption spectrum of the optical recording medium by optical Stark effect.