DISTRIBUTED REFRACTIVE INDEX TYPE OPTICAL ELEMENT AND DISTRIBUTED REFRACTIVE INDEX TYPE ROD LENS ARRAY

摘要

PROBLEM TO BE SOLVED: To provide a core/cladding distributed refractive index type optical element preventing optical characteristics based on the part where the refractive index is deviated from the normal parabolic distribution from deteriorating, at the same time preventing flare light from invading and having excellent resolution even in the case being used for the optical device influenced by the near infrared ray region and a rod lens array using the same. SOLUTION: In the distributed refractive index type optical element with a core/cladding structure containing a metal oxide coloring component in the cladding glass and manufactured with the ion exchange method, the distributed refractive index type optical element is characterized by comprising the cladding glass which contains 0.5-4.0 wt.% CoO and 2.0-12.0 wt.% total iron oxide (expressed in terms of Fe2O3) as the metal oxide coloring component taking the total amount of the mother glass components excluding the coloring component as 100 wt.% and which contains FeO expressed in terms of Fe2O3 occupying 23-75% of the total iron oxide.