POLARIZING GLASS PLATE AND METHOD FOR MANUFACTURING SAME, POLARIZING GLASS PLATE SET FOR OPTICAL ISOLATOR, AND METHOD FOR MANUFACTURING OPTICAL ELEMENT FOR OPTICAL ISOLATOR

摘要

Provided is a method for easily manufacturing a polarizing glass plate in which polarizing axis misalignment is reduced. A method for manufacturing a polarizing glass plate in which stretched metal particles are dispersed in an aligned manner in a glass matrix, wherein the method for manufacturing a polarizing glass plate is characterized in including: a stretch-molding step for stretch-molding, while heating, a glass preform plate (1) having a prescribed width W₀ and containing metal halide particles (4), and thereby obtaining a glass member (5) in which stretched metal halide particles (4') are dispersed in an aligned manner in a glass matrix; and a reduction step for performing a reduction process on the glass member (5) to reduce the stretched metal halide particles (4') and obtain a polarizing glass plate, the glass preform plate (1) being stretch-molded while being heated, in the stretch-molding step performed on the glass preform plate (1), such that the shape of the glass preform plate (1) during stretch-molding satisfies the following relationship (1). L₁/W₁ ≥ 1.0 …(1) L₁ = length between portion (a) at which the width of the glass preform plate (1) has changed to 0.8 times the original width (W₀) and portion (b) at which the width of the glass preform plate (1) has changed to 0.2 times the original width. W₁ = length equivalent to 0.5 times the original width W₀ of the glass preform plate (1).