Optical device, optical system, method of production of same, and mold for production of same

A method of production of an optical device comprising a first optical portion made of a first optical material and having a concavity and a second optical portion comprising a second optical material having a refractive index different from that of the first optical material, wherein the second optical portion is inserted into the concavity, the method of production comprising the steps of:

• injecting the first optical material into a metallic mold formed with a projection that projects out into a cavity to form the first optical portion having a concavity that reproduces the shape of the projection;
• and
• a step of filling the second optical portion in the concavity of the molded first optical portion, further comprising a step of flattening a surface of the second optical portion filled in the concavity, wherein;
• the concavity of the first optical portion has a substantially rotationally symmetric shape with respect to an optical axis, and the section of shape of the surface of the concavity is substantially an arc, and
• in the flattening step, the surface of the second optical portion is polished so that a flat plane substantially vertical with respect to the symmetry axis of the concavity reproducing the shape of the projection is formed.