Data Storage

Introduction

Optical data storage has the merits of large capacity, long lifetime and low energy consumption, becoming a significant data storage technology in the information age. Persistent luminescence materials are one of the most important parts in optical data storage due to that show the excellent photon storage ability under exposure of short-wavelength electromagnetic waves.

Figure 1. The electronic data storage

Mechanism

With a large quantity of persistent luminescence materials being discovered in the last 30 years, the mechanism has been extensively discussed.^[1]

• During recording, the luminescent centers are excited by the incident high-energy photons.
• A part of the excited electrons move to neighboring trap centers via the conduction band (CB) of the host.
• When the energy of the photostimulation is close to the trap depth, the photostimulation offers another effective detrapping route by the direct electron transition from the trap level to the CB.
• If the trap depth is much greater than the thermal activation energy at RT, the release rate of the trapped electrons by spontaneous thermal activation is rather low, resulting in the incident photon energy frozen in the luminescence materials.
• In the readout process, the phosphor film is heated up to a higher temperature, which provides the trapped electrons with the sufficient activation energy to release from the trap levels.
• The electrons recombine with the luminescent centers, and give the photon emission.

Figure 2. The mechanism for the photon storage and release processes.

Advantages

Compared with other storage methods, optical storage has the following advantages:

• Optical storage has the advantages of resisting natural disasters, magnetic storms, and man-made data deletion.
• Optical storage consumes almost no energy when storing information, only consumes energy when reading and writing, and does not require air conditioning to dissipate heat. In the case of long-term storage (more than 12 years), the energy consumption of optical storage is only 1/500 of that of hard disk storage.
• Optical storage is reliable and has a long-life span, and high-quality optical storage media can reach more than 50 years. Therefore, optical storage is conducive to long-term safe storage of information.
• Compared with several storage media such as semiconductor memory, hard disks, and magnetic tapes, optical disks have a significant advantage of low cost per unit storage capacity. Optical storage can use multiple storage technologies such as multi-level, multi-dimensional, and nano-super-resolution, and the storage density will be significantly increased to the terabyte level.

What Can Alfa Chemistry Do?

Alfa Chemistry's technical R&D team has focused on the preparation and application of persistent luminescence materials for many years, which has established long-term cooperative relationships with many well-known enterprises and research institutions. We have conducted research on various problems encountered by data storage, which can select the appropriate solution according to the customer's experimental purpose. The data storage technologies we provide are as follows:

• We can provide the technology of preparation of the phosphor films.
• We can provide the technology of laser-write-in and laser-readout.
• We can provide the repeatability test of data storage.

Reference

• Zhuang Y.; et al. Optical data storage and multicolor emission readout on flexible films using deep-trap persistent luminescence materials. Adv. Funct. Mater., 2018, 28(8): 1705769-1705778.