Article**Since *** Advanced Manufacturing".
The era of big data, the amount of information is increasing. According to the statistics of the international authoritative IDC, the global data volume is expected to reach a staggering 175 ZB (1 ZB 11 trillion GB), how to store this data securely, efficiently and at low cost has become an urgent problem to be solved.
At present, the storage and archiving of data mainly rely on semiconductor flash memory devices and hard disk drives, which have the disadvantages of high energy consumption, high cost, and short lifespan. Optical data storage (ODS) technology has the unique advantages of green energy saving, safe and reliable, and a lifespan of up to 50 to 100 years, which is very suitable for long-term low-cost storage of massive data. However, due to the limitation of optical diffraction, the maximum capacity of traditional commercial optical discs is only in the order of 100 GB. How to effectively increase the storage density and increase the storage capacity of a single disk in a limited volume has long been a major challenge in the field of optical storage. In order to improve the storage density of optical storage media, the researchers mainly adopted two methods: the first is a multi-dimensional optical storage technology based on the multiplexing of physical quantities, such as the surface plasma characteristics of metal nanorods and the birefringence phenomenon of nanogratings in fused silica to multiplex physical quantities such as intensity, polarization state, orbital angular momentum and other physical quantities for multi-dimensional information storage; The second is a multi-layer-based three-dimensional optical storage technology that writes multiphotons in materials such as photochromic materials, photorefractive polymers, or crystals. However, the above two methods do not break through the limitation of the optical diffraction limit, and the channel spacing of adjacent recording points is greater than the size of the diffraction limit, and the equivalent capacity of a single disc is only in the order of terb. The limitation of the optical diffraction limit topped the field of physics among the 125 most cutting-edge scientific problems published by Science in 2021, and it is also one of the seven technical areas that will be focused on in the coming year in 2024 by Nature. In order to break through the limits of the diffraction limit, the German scientist Stefan WProfessor Hell proposed stimulated emission depletion (STED) and won the Nobel Prize in Chemistry in 2014. In 2013, Academician Gu Min realized the 9 nm laser direct writing technology using the principle of double beams. However, it is extremely challenging to realize super-resolution optical storage based on the STED-like mechanism, because the storage medium not only needs to have an on-off rejection channel with on-off characteristics, but also realizes super-resolution write and readout, which can be stored in three dimensions, and the material must have stable performance and be easy to store for a long time.
Recently, researchers from the University of Shanghai for Science and Technology, the Shanghai Institute of Optics and Fine Mechanics of the Chinese Academy of Sciences and other researchers have made major breakthroughs in the field of ultra-large capacity 3D nanophoton storage. The results were announced on 22 February".a 3d nanoscale optical disk memory with petabit capacity(Pb level storage capacity 3D nano disc memory) was published innatureAbove. 
Dean of the Institute of Photonic Chips, University of Shanghai for Science and Technology, Director of the Institute of Optical Computing, Zhangjiang LaboratoryAcademician Gu Min, Shanghai Institute of Optics and Fine Mechanics, Chinese Academy of SciencesResearcher Hao Ruan, University of Shanghai for Science and TechnologyProfessor Wen Jingis the co-corresponding author of this article; , Shanghai Institute of Optics and Fine Mechanics, Chinese Academy of SciencesPostdoctoral fellow Miao Zhaoand University of Shanghai for Science and TechnologyProfessor Wen JingHe is the joint first author. , Shanghai Institute of Optics and Fine Mechanics, Chinese Academy of SciencesPh.D. student Hu Qiao, Peking UniversityProfessor Wei Xunbinand the Institute of Chemistry, Chinese Academy of SciencesProfessor Zhong YuwuParticipated in the study.
The equivalent capacity of a single disc is as high as petabyte, which is 10,000 times higher than that of existing optical discs
The researchers have developed an organic resin film doped with aggregation-induced luminescence dye (DIE-DOPED Photoresist with aggregation-induced eEmission (AIE-DDPR). It has several important properties. First, super-resolution nanoscale optical writing is based on a triplet-triplet absorption mechanism. The interaction between the annular beam and the organic resin effectively inhibited the polymerization effect of the organic resin by using the triplet-triplet absorption effect. Secondly, for data readout, the optically stimulated aggregation-induced emission (OS-AIE) based on laser excitation can selectively enhance the fluorescence intensity emitted by the writing region, and the ring light is also used to suppress the fluorescence enhancement phenomenon. Finally, STED microscopy was used for super-resolution readout. Such as:Figure 1The schematic diagram of the reading and writing principle and preparation process of 3D nano-optical disc is shown, and finally the super-resolution data storage with a point size of 54 nm and a channel spacing of 70 nm is realized, and a multi-layer recording of 100 layers is completed, which is equivalent to a single disk with an equivalent capacity of up to the order of petabytes, which is equivalent to at least 10,000 Blu-ray discs or 100 commercial hard disks. It is worth mentioning that the AIE-DDPR material not only has a life span of more than 40 years, but also is compatible with the standard process flow of traditional optical disc mass production, which has a very promising application prospect. 
Figure 1: Schematic diagram of the reading and writing principle and production and preparation process of 3D nano-optical disc Source: Nature 626, 772 778 (2024) The standard size of optical disc is 120 mm in diameter, based on the material and method of this **, the equivalent capacity and storage surface density calculated with 100 layers on each side are better than all current high-performance storage systems, thousands of times that of the most advanced optical discs, and 10,000 times higher than the capacity of common commercial Blu-ray discs on the market. 
Figure 2: Key metrics of AIE-DDPR and existing high-performance storage systems.
Source: Nature 626, 772 778 (2024).
Super-resolution optical storage technology for laser-tunable aggregation-induced luminescence dyes (OS-AIE).
In addition, this study is the first to report the aggregation-induced luminescence phenomenon (OS-AIE) under femtosecond laser control, and to deepen a series of new mechanistic processes. Figure 3The state change of AIE-DDPR material from colloidal (first state), UV curing (second state) and femtosecond laser beam (third state) is revealed. AIE-DDPR material only emits weak fluorescence when it is in the second state. When the solid femtosecond laser at 515 nm induces the transition from the second state to the third state, the film is further polymerized, resulting in the enhancement of aggregation-induced luminescence intensity, and the emission spectrum of the third state is redshifted relative to the second state. However, the ring-shaped 639 nm CW laser has a triplet-triplet absorption effect with the material, which prevents the above process in the peripheral region. With the increase of laser power, the fluorescence emission enhancement of the third state in the wavelength range of 490 550 nm is more intense, and the fluorescence contrast of the recording point can reach 60:1. 
Figure 3: Mechanism of action of Femtosecond laser-induced OS-AIE Source: Nature 626, 772 778 (2024) Researchers believe that femtosecond laser can not only improve the intensity of fluorescence generation while improving the aggregation state of materials, but also realize the movement of the emission spectrum, so that the information recording point can maintain a high fluorescence contrast at the super-resolution scale within the detection range and achieve super-resolution readout.
Summary
In this paper, a super-resolution optical storage technique for laser-tunable aggregation-induced luminescent dyes (OS-AIE) is proposedIt is of great significance for China to break through the key core technical barriers in the field of information storage and realize the sustainable development of the digital economy by breaking through the key core technical barriers in the field of information storage and reading out the information, and increasing the equivalent capacity of a single disk to the order of petabytes. In the future, the OS-AIE principle may have considerable application potential in the fields of high-resolution display of organic light-emitting diodes, biological microscopy, photonic chip light sources, etc. Academician Gu Min pointed out that the next step will be to develop industrialization-oriented nano-scale photonic storage technology to meet the massive data storage needs in the era of big data, and its cost, energy consumption and space will be much lower than the current optical disk library and HDD data cabinet storage technology. Dividing line ---
Cross-scale nanoscale 3D femtosecond laser direct writing equipment
Shanghai Jinlei Optoelectronics coordinates the system developed by Huazhong University of Science and Technology to provide nano-scale high-precision maskless lithography and nano-scale 3D micro-nano structure printing, and with the customized software system, it can intelligently complete the manufacturing of high-precision maskless lithography and laser direct writing lithography of other nano-scale 3D devices.