An infrared absorption filter consisting of 70 to 98 mol % of SiO2,
1 to 12 mol % of CuO and 1 to 18 mol % of a network modifier oxide than CuO or
CdO is provided. A process of fabricating an infrared absorption filter is also
provided. The process comprises introducing a divalent copper compound and a compound
of a metal species acting as a network modifier oxide in the form of metal ions
into a wet gel. The wet gel can be dipped in a dipping solution to precipitate
the divalent copper compound and the compound of a metal species acting as the
network modifier oxide in the wet gel. The wet gel can be dried and heated, thereby
obtaining an infrared absorption glass. The infrared absorption glass can be cut
and polished, thereby fabricating a filter.
