A research group led by Prof. ZHANG Jiahua from Changchun Institute of Optics, Fine Mechanics and Physics of the Chinese Academy of Sciences and his co-author Prof. LIU Feng from Northeast Normal University, Prof. WANG Xiaojun from Georgia Southern University proposed a single-wavelength information write-in and read-out strategy to replace the conventional multi-wavelength strategy to simplify the structure of storage devices. The work was published in Laser & Photonics Reviews.

Optical information storage technique has developed tremendously in the past few decades due to its advantages such as large capacity, small size, long lifetime, environmental friendliness and low power consumption. Electron trapping optical storage is considered to be one of the most promising storage techniques due to its unique energy storage method and controllable photon release mode.

Simple near-field configuration is the key to miniaturization and integration of optical storage devices. Therefore, simplifying the structure of electron trapping optical storage devices is of great significance for the development of integrated optical storage systems.

This work utilizes the “ladder-like” energy level structure of Pr³⁺ to design information write-in through up-conversion charging under high-power-density (> 0.03 W/cm²) blue laser excitation, and then information read-out under low-power-density (< 0.03 W/cm²) stimulation of the same laser. The design has been verified in the binary information encoding and decoding experiment of Y₃Al₂Ga₃O₁₂:Pr³⁺,Eu³⁺ electron trapping medium. Further, the introduction of Eu³⁺ creates deep traps for trapping electrons, which facilitates the long-term storage of information.

This research not only develops an excellent long-term optical storage medium, but also effectively simplifies the near-field configuration of the electron trapping optical storage devices, opening up a new perspective for the development of integrated optical storage systems.