3‐D optical data storage by two‐photon excitation

Increased data density and media capacity is a constant goal of research into optical storage. These‐dimensional optical storage offers this large increase because the volume density limit is 1/λ 3 rather than the 1/λ 2 achievable with 2‐D storage. Holographic storage and spectral hole burning have been examined in the past; here an alternative is presented based on two‐photon excitation.