Patent ID: 7498103

Claim:
A holographic recording medium, comprising a recording layer containing a three dimensionally cross-linked polymer matrix including an epoxy compound, a radically polymerizable monomer, and a photo radical polymerization initiator, the epoxy compound comprising a compound that is in the form of a liquid at 20° C. or less and being selected from the group consisting of 1,4-butanediol diglycidyl ether, 1,6-hexanediol diglycidyl ether, diethylene glycol diglycidyl ether, polyethylene glycol diglycidyl ether, polypropylene glycol diglycidyl ether, neopentyl glycol diglycidyl ether, diepoxy octane, resorcinol diglycidyl ether, diglycidyl ether of bisphenol A, diglycidyl ether of bisphenol F, 3,4-epoxy cyclohexenyl methyl-3′,4′-epoxy cyclohexene carboxylate and polydimethyl siloxane of epoxy propoxypropyl terminal, the radically polymerizable monomer comprising both N-vinylcarbazole and N-vinylpyrrolidone or N-vinylcarbazole alone, and the weight ratio satisfying the following relationship: 0.75≦ VC /( VC+VP )≦1.0 wherein VC is weight of N-vinylcarbazole and VP is weight of N-vinylpyrrolidone.