Advantageous recording media for holographic applications
View Patent ↗High performance media suitable for recording with a blue laser is disclosed. The blue-sensitized holographic media provides greater dynamic range and higher sensitivity than previously disclosed blue-sensitized holographic media. These media can be used for diverse applications such as data storage where the articles provide denser data storage and more rapid hologram writing times or for optical waveguides where the articles provide greater optical confinement and more rapid manufacturing times.
1. An optical article comprising a photoactive monomer with molecular weight greater than 500 and a photoinitiator incorporated in a polymer matrix, wherein the optical article has an initial absorbance between 330 and 490 nm and wherein the polymer matrix is formed by a polymerizing reaction of a material comprising component 1 and component 2, said component 1 comprises an NCO functional component and said component 2 comprises a polyol and wherein an excess amount of at least about 10% polyol is used.
2. The optical article of claim 1 wherein the optical article has a refractive index contrast greater than 3×10 −4 .
3. The optical article of claim 1 wherein the optical article has a refractive index contrast adjusted sensitivity of greater than 1×10 −6 Δn/mJ/cm 2 .
4. The optical article of claim 1 , wherein the photoinitiator comprises an acylphosphine oxide or an oxime ester or combinations thereof.
5. The optical article of claim 1 , wherein the organic photoinitiator is selected from the group consisting of
and combinations thereof.
6. The optical article of claim 1 , wherein the photoactive monomer is multifunctional.
7. The optical article of claim 6 wherein the photoactive multifunctional monomer comprises an acrylate group.
8. The optical article of claim 1 , wherein the optical article is selected from the group consisting of an optical waveguide and a holographic recording medium and combinations thereof.
9. The optical article of claim 1 , wherein the optical article has a writing induced shrinkage of less than 0.25 percent.
10. The optical article of claim 1 , wherein the photoinitiator is substantially free of a transition metal complex.
11. The optical article of claim 1 , wherein a free radical retarder is added.
12. The optical article of claim 11 , wherein the free radical retarder is one or more of the following: benzhydrol, triphenylmethane, tris(thiophenyl)methane, diphenylmethane, aniline, hindered phenol, and ether derivatives of benzhydrol.
13. The optical article of claim 1 , wherein the formulation further comprises a plasticizer.
14. The optical article of claim 13 , wherein the said plasticizer is one or more of the following: dibutyl phthalate, low molecular weight amides with boiling points greater than 100° C., low molecular weight esters with boiling points greater than 100° C., and low molecular weight polyethers.
15. The optical article of claim 1 , wherein the polymerizing reaction is promoted by a catalyst.
16. The optical article of claim 15 , wherein said catalyst is a Lewis acid catalyst based on metal complexes containing metals such as zinc, manganese, iron, tin, and zirconium.
17. The optical article of claim 1 wherein the article contains two substrates encasing the polymer matrix.
18. The optical article of claim 17 wherein at least one of the substrates contains a surface relief or tracking pattern.
19. The optical article of claim 17 wherein at least one of the substrates is coated with an anti-reflection coating on its outer surface.
20. The optical article of claim 1 wherein the article is housed within a cartridge.
21. A method for holographic recording in an optical article comprising exposing the optical article to blue light and writing a hologram in the optical article, the optical article comprising a multifunctional photoactive monomer with molecular weight greater than 500 and an organic photoinitiator incorporated in a polymer matrix, wherein the optical article has an absorbance less than 0.5 at wavelengths between 400 and 490 nm and has a refractive index contrast adjusted sensitivity of greater than 3×10 −6 Δn/mJ/cm 2 and wherein the polymer matrix is formed by a polymerizing reaction of a material comprising component 1 and component 2, said component 1 comprises an NCO functional component and said component 2 comprises a polyol and wherein an excess amount of at least about 10% polyol is used.
22. A method for manufacturing an optical article comprising polymerizing a material comprising component 1 and component 2 and forming the optical article, the optical article comprising a multifunctional photoactive monomer with molecular weight greater than 500 and an organic photoinitiator incorporated in a polymer matrix, wherein the optical article has an absorbance less than 0.5 at wavelengths between 400 and 490 nm and has a refractive index contrast adjusted sensitivity of greater than 3×10 −6 Δn/mJ/cm 2 and wherein the polymer matrix is formed by a polymerizing reaction of a material comprising component 1 and component 2, said component 1 comprises an NCO functional component and said component 2 comprises a polyol and wherein an excess amount of at least about 10% polyol is used.