Refractive index distribution type optical element and refractive index distribution type rod lens array

摘要

A refractive index distribution type optical element has a core/cladding structure produced with the ion exchange method. The element includes colorant of metal oxides in cladding glass thereof. The cladding glass consists of base glass and the colorant of the metal oxides comprising: 0.3 to 4.0 wt. % CoO; 1.0 to 12.0 wt. % Fe2O3; 0.0 to 2.0 wt. % NiO; and 0.0 to 0.2 wt. % Cr2O3 when the total amount of the base glass except for the colorants is taken as 100 wt. %. The refractive index distribution type optical element is prevented from deterioration of the optical properties occurring at portions having the refractive index departing the regular parabolic distribution and also is prevented from entrance of the flare light. The element is provided with good resolution even when employed for an optical device using a white light, and a rod lens array formed with the refractive index distribution type optical element is provided.