| 摘要 |
PURPOSE:To obtain the extreme value characteristics of transmittance at an assigned wavelength by alternately laminating high- and low-refractive index layers on the incident side surface of a substrate consisting of the same material as the material of the high-refractive index layer and constituting antireflection films consisting of the low- and high-refractive index layers on the exit side surface of the substrate. CONSTITUTION:Reflecting films 10 are formed on the substrate 1 by alternately laminat ing the low-refractive index layers 2 and the high-refractive index layers 3. The sub strate 1 consists of the same material as the material of the high-refractive index layers 2. The antireflection films 20 are then formed on the exit side surface 1b. The films 20 consist of the two-layered constitution of the low-refractive index layer 2 and the high-refractive index layer 3. A beam splitter film for a CO laser is installed with 45 deg. inclination to an incident laser beam 30 and reflects a laser beam 30 at a prescribed reflectivity R. The beam light entering the inside of the substrate 1 of the incident laser beam 30 passes and transmits the films 20. The extreme value charac teristic of the reflectivity near the wavelength of the incident laser beam 30 is obtd. in this way and the stability to the fluctuation of the wavelength of the incident laser beam 30 is obtd. |
