Optical filters comprising solar blind dyes and UV-transparent substrates

A method of making an optical filter comprising:

• a. an organic, solar blind filter dye;
• and
• b. a UV-transparent, non-scattering and chemically stable substrate,
• comprising the steps of:
• (1) selecting a nanoporous silica glass solid that is substantially UV-transparent;
• (2) dissolving said dye in a UV-transparent solvent, which has been selected to form a solution of said dye and to match the refractive index of the nanoporous silica glass solid;
• (3) allowing said solution to permeate said porous glass solid to form a UV-transparent, non-scattering substrate incorporating said dye.

A method of making an optical filter comprising:

• a. an organic, solar blind filter dye;
• and
• b. a UV-transparent, non-scattering and chemically stable substrate,
• comprising the steps of:
• (1) selecting a nanoporous silica glass solid that is substantially UV-transparent;
• (2) dissolving said dye in a relatively volatile solvent to form a volatile solution;
• (3) allowing said volatile solution to permeate said nanoporous glass solid;
• (4) evaporating off the relatively volatile solvent, leaving behind microparticles of said dye in the pores of the nanoporous silica glass solid;
• and
• (5) allowing a relatively non-volatile, UV-transparent solvent, which has been selected to match the refractive index of the nanoporous glass solid, to permeate the nanoporous glass solid containing microparticles of said dye until said dye is dissolved in the non-volatile solvent, thus forming a UV-transparent, non-scattering substrate incorporating said dye.

A method of making an optical filter comprising:

• a. an organic, solar blind filter dye;
• and
• b. a UV-transparent, non-scattering and chemically stable substrate,
• comprising the steps of:
• (1) grinding together a UV-transparent inorganic salt with said dye to form a mixture;
• (2) compressing said mixture to form a solid body.