Single-shot photon recording for three-dimensional memory with prospects of high capacity

Femtosecond laser-induced modification in the glass has drawn considerable interest due to its widespread superiority in the applications of three-dimensional optical storage. In this Letter, we report that a single pulse could be used in optical memory with super-high writing speed. The photoluminescence image and spectrum indicate that one pulse-induced permanent photoreduction of Sm³⁺ to Sm²⁺ in Sm³⁺-doped sodium aluminoborate glass can be achieved. Consequently, strong emission contrast is obtained, which is used for optical storage. By regulating the fabrication conditions, the fluorescent diameter could be controlled to approximately 800 nm, which demonstrates the feasibility in super-high density optical storage. Besides, multi-layer information is successfully inscribed. The proposed technique of single-pulse writing holds great potential for optical memory with high speed and huge capacity.