JPS5625707A - Polarizing prism - Google Patents

Abstract

PURPOSE: To separate a ray efficiently by forming a prism like a triangle pole whose section is a right-angled triangle, by use of substance having double refraction, making one of both the sides of a right angle of the sectional triangle parallel with the optical axis, making the opposite angle an inverted tangent of ratio of the refractive index of an abnormal ray and a normal ray, and giving an incident ray vertically to both the sides of the right angle.

CONSTITUTION: One of both the sides (b) and (c), for instance, (b) of the right angle of a right angle prism which has been made of substance having double refraction, for instance, calcite is made to conform with the optical axis of a crystal, and the opposite angle θ of the side (b) is made equal to an inverted tangent of ratio of the refractive index of an abnormal ray to the refractive index of a normal ray. When an incident ray (B) has been given vertically to the side (C) of both the sides of the right angle, a polarized ray whose electric field is vertical to the paper surface is reflected by the base (a) by the reflective angle θ which is equal to the incident angle θ, and is emitted in the direction (C). On the other hand, a polarized ray whose electric field is on the paper surface is reflected at the angle of θ+α and is emitted in the direction (D) vertical to the side (b). Also, in case of an incident ray vertical to the side (b), a polarized ray whose electric field is on the paper surface is emitted in the direction (E) making a right angle with the side (C). A polarized ray vertical to the paper surface is emitted in the direction (F) which is larger by α angle. Thus a ray can be separated efficiently.

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