| 摘要 |
PURPOSE:To improve the diffraction efficiency over the entire area of a hologram without generating an astigmatism by previously applying the astigmatism for correcting aberrations so as to form an point image at the time of reproduction on an object light side. CONSTITUTION:A hologram sensitive material 1 consisting of a photopolymer, etc., is irradiated with reference light 2 and object light 3 parallel therewith. Bluish green lasers of about 441 to 528nm which can sensitize the photopolymer are used for the respective light beams 2, 3. The astigmatism of the object light 3 by the wavelength difference from the reproduced light is previously calculated and the diversion points of the object light (meridian) 3 and the object light (spherical segment) 4 are held apart by as much as the previously calculated aberration component. The method of applying such aberration is attained by using a cylindrical lens 5 and applying the astigmatism with the meridian plane and the spherical segment plane. The hologram image having the aberration with the meridian plane and the spherical segment plane is recorded on the hologram sensitive material 1 in such a manner. The image in which the aberrations of the object light beams 3, 4 are offset by the astigmatism based on the wavelength difference between the reference light an the reproduced light is obtd. when the reproduced light conjugate with the reference light 2 is made incident perpendicularly on the hologram sensitive material 1 at the time of reproduction. |
