| 摘要 |
PURPOSE:To obtain a distributed index type lens which has a large numerical aperture, permits easy production and has high stability by forming said lens of a chalcogenide substrate having a part where a metal is diffused to provide a desired refractive index distribution. CONSTITUTION:Metallic molecules or atoms are easily diffused into the chalcogenide glass of the part irradiated with an electron beam and the refractive index of the diffused part increases when the electron beam is irradiated onto the thin metallic film formed on the chalcogenide glass. More specifically, a thin film 2 consisting of the metal is formed on the chalcogenide glass substrate and the electron beam 3 is irradiated from the thin metallic film 2 side to the chalcogenide glass substrate 1, then the molecules or atoms of the metallic material forming the thin metallic film 2 diffuse to the part of the chalcogenide glass where the electron beam is irradiated. The prescribed distributed index type lens is formed if the thin metallic film of the part except the part where the electron beam is irradiated is removed. |
