To reduce stray light by forming a light absorbing material layer absorbing light at a wavelength equal to that of light emitted from a semiconductor laser on at least one side face.
A hologram element is provided with a hologram pattern 2 on the upper face of a core material 1. In the core material 1, the whole of the side faces, only the two side faces, or the periphery of the hologram pattern 2 in the upper part is covered by a light absorbing material layer 3 absorbing light at a wavelength equal to that of emitted light from a semiconductor laser. As the light diffraction condition is absorbed and stray light is reduced, stray light generated from light flux passing though the inside of the hologram element is also reduced. Desirably, the light absorbing material layer 3 is made of the same material as the hologram pattern 2. In production of the hologram element, a plurality of core parts are connected together via runners by integral molding, the light absorbing material layer 3 is molded integrally with the integrally molded core parts, and then, each element is cut out by dicing or the like.
Hamaoka, Osamu
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