An optical filter element having high isolation and reduction in
reflection loss for input light beams. The optical filter element is used
with a transparent substrate having a surface that includes a first area
and a second area. The optical filter element has a target wavelength
range. The optical filter element includes a first dielectric multilayer
film arranged in the first area of the transparent substrate. A second
dielectric multilayer film is arranged in the second area of the surface
of the transparent substrate. The second dielectric multilayer film has a
reflectance of a predetermined value or less for a light beam having a
wavelength in the target wavelength range. A portion of the second
dielectric multilayer film and a portion of the first dielectric
multilayer film are laminated each other.