| 摘要 |
PROBLEM TO BE SOLVED: To make initialization efficient by densifying and uniformizing a high output laser beam size through a collimate lens, an objective lens and an anamorphic prism. SOLUTION: A high output semiconductor laser LD 1 is made a parallel luminous flux by the collimate lens 2, and is refracted only in the direction parallel to the longitudinal direction of the activated layer of the LD 1 by an anamorphic prisms pair 3 of an anamorphic optical system, and its luminous flux size is enlarged. The enlarged luminous flux is converged on a joined surface of a recording layer 52 of an optical recording medium 5 in parallel by the objective lens 4 through a λ/4 wavelength plate 10'. The luminous flux size of the LD 1 at the time is decided by the focal distances of the used collimate lens 2, objective lens 4 and the magnification of the anamorphic prisms pair 3. At this time, since a beam size becomes 1/2-1/6 of a half-value width of a near view image in the direction parallel to the joint surface of the LD 1, an intensity profile becomes dense. Thus, the apparently uniformized intensity profile is realized, and the even initialization is performed efficiently. |
