Abstract: This invention comprises a novel apparatus for recording a holographic groove pattern on a diffraction grating blank. The recording apparatus is configured using newly developed groups of analytical equations. The invention further comprises the novel holographic diffraction grating made with the inventive recording apparatus. The invention additionally comprises monochromators and spectrometers equipped with the inventive holographic diffraction grating. Further, the invention comprises a monochromator configured to reduce aberrations using a newly developed group of analytical equations. Additionally, the invention comprises a method to reduce aberrations in monochromators and spectrometers using newly developed groups of analytical equations.

Abstract: In the information recording an reproducing method and apparatus according to the present invention, picture image information is recorded as an analog quantity or a digital quantity on an information carrying medium in a planar manner at a high density, charge potential is read for outputting electric signals to correspond to the recorded picture image information and then the outputted signals are printed out by means of various display unit or output device, with high quality and high resolution as well as ease processing of the information. The information carrying medium provides a long period of storage of information and enables stored picture image information to be repeatedly reproduced with a picture quality according to need.

Abstract: In the information recording an reproducing method and apparatus according to the present invention, a piece of picture image information is recorded as an analog quantity or a digital quantity an information carrying medium in a planar manner at a high density, charge potential is read for outputting electric signals to correspond to the recorded picture image information and then the outputted signals are printed out by means of various display unit or output device, with high quality and high resolution as well as ease processing of the information. The information carrying medium provides a long period of storage of information and enables stored picture image information to be repeatedly reproduced with a picture quality according to need.

Abstract: In formulating a groove pattern for a diffraction grating by means of holography, unique groove patterns are obtained by use of astigmatic coherent beam as either one or two recording beams. Instead of use of only stigmatic beams, and astigmatism in recording light in manufacture of a halographic grating will bring more utilizable parameters in designing groove patterns by which new loci of the type of non-hyperboloidal curves are formed on grating substrates and thereby elimination of abberations which were conventionally difficult are achieved with various optical devices.

Abstract: A composite power cable includes an elongated cable core having an electrical conductor and a shield layer of a semiconductive material. The cable includes an outer sheath of a first thermoplastic resin encompassing the cable core. A plurality of concentric neutral wires are embedded in the outer sheath and helically wound around the cable core. At least one elongated flexible optical fiber unit is embedded in the outer sheath and helically wound around the cable core so as to extend along the neutral wires. The fiber unit includes an elongated body of a second thermoplastic resin extending longitudinally thereof, at least one flexible tube embedded in the body to extend longitudinally thereof, at least one optical fiber loosely received in the tube to extend longitudinally thereof and at least one elongated tension member embedded in the body to extend longitudinally thereof.

Abstract: A constant deviation monochromator with a holographically formed concave grating and entrance and exit slits positioned on opposite sides of the plane including the Rowland circle of the grating, wherein the grating has been formed by using two coherent light sources positioned on the same side of the Rowland plane, whereby aberrations and stray light are substantially reduced.