| 摘要 |
PROBLEM TO BE SOLVED: To make it possible to distinctly discriminate the front and rear of a bismuth substd. rear earth iron garnet single crystal (BIG) film for a Faraday rotor having antireflection films to light of a specific wavelength formed on both front and rear surfaces by color tones by varying the hue of the front and rear of the BIG film. SOLUTION: The BIG film for the Faraday rotor having the antireflection films to the light of the wavelength of >=1nm formed on both front and rear surfaces, is so formed that the front and rear of the BIG film vary in the hue. Namely, if the media of the antireflection films or the thicknesses of the media vary, the patterns entirely different in the transmittance and reflectivity are formed in the visible region from a wavelength of 400 to 800nm and, therefore, the differences in color tones appear. If, consequently, the antireflection films to be applied on both surfaces of the BIG film are so formed as to be the same in their functions and to vary with the front and the rear, the colors of the front and the rear eventually vary in the visible region and are easily discriminative. SiO2 , MgF2 , Al2 O3 , etc., are usually and generally used for the materials (media) of the antireflection films. |
