Dear sirs,
we're doing a feasibility study of an optical system where a set of
about 1,000 elementary spherical lenses, made of fused silica,  should
be glued together in a single unit (a sort of "window-lens"). Our
problem is the trasmission
through the glue layer: we need a good transmission in the range between

2500 and 4000 Angstroms of wavelength, with a glue layer thickness that,

on our opinion, should be around 0.1 mm, perhaps something less. Can You

suggest us an optical adhesive that could comply with our requirements?
We've heard that some companies can do a low temperature fusion welding
process, without using any glue: can You give us the directions to reach

such companies?
Best regards