| 摘要 |
PURPOSE:To mass-produce small-sized diffraction gratings having a high line density, by producing a large-sized glass base material having a structure similar to that of a desired diffraction grating and heating an enlarging this base material. CONSTITUTION:Grooves 3 are formed on a side face 2 of an angular quartz glass bar 1, and fine glass particles are accumulated on the side face 2, and the bar 1 is heated at about 1,450 deg.C to make the glass transparent, and thus, a glass layer 4 is formed. This glass bar is heated at about >=1,800 deg.C and is enlarged to obtain a glass bar 1' which has a parallel stripe-shaped structure 3 on a side face 2', and the side face 2' is etched to obtain a glass base material 1'' having narrow grooves 3'. A metal such as gold having a high refraction factor is vapor-deposited onto narrow grooves 3' of the base material 1'', and the base material 1'' is sliced in the direction orthogonal to the direction of enlargement, and upper and lower faces of a sliced material are polished optically to obtain a plane plate 21a where a reflective diffraction grating 23a is provided in the end face. |
