We propose what we believe to be a novel holographic recording technique to improve the recording speed for holographic data storage (HDS). In this technique, holograms are recorded by scanning a digital micromirror device (DMD) that displays a data page with a focused, power density-increased line beam while synchronously shifting the recording medium and a spherical reference wave. This approach eliminates the stop-and-go motion of driving mechanisms, enabling rapid, continuous, multiplexed recording. Although the recorded localized holograms retain only partial information about the data page, the entire page can be reconstructed simultaneously using the spherical reference wave. Experimental demonstrations achieved a bit error rate (BER) of less than 10% at a 5ms exposure time and stable multiplexed recording at 150Hz. The proposed technique represents a significant step toward the realization of practical HDS systems.

Holographic data storage (HDS) has attracted considerable interest as a promising route to large-capacity and high-density recording, enabled by volume multiplexing, high transfer rates, and parallel readout. Here, we propose a high-dimensional data storage scheme based on petal optical vortex (POV) multiplexing holography (HDDS-POVMH), where multiple information layers are encoded into a single global multiplexed hologram. By exploiting the dual degrees of freedom (ℓ, φ) of the POV, ℓ provides layer addressing while φ enables M-ary pointwise phase modulation, and the stored symbols are reconstructed using an intensity-based phase decoding (IPD) algorithm from the retrieved dot-array intensities. The storage capacity scales with the dot-matrix sampling points per layer, the M-ary phase alphabet set by φ, and the number of ℓ-addressed multiplexed layers supported by POV orthogonality. In representative single- and dual-layer demonstrations, IPD achieves error-free symbol reconstruction, supporting a reliable and scalable high-dimensional HDS framework. This HDDS-POVMH scheme exhibits significant potential for next-generation high-volume archival systems, large-scale data repositories, and optical-network storage applications.

The cross-linked photopolymer vinyl-POSS (Vi-POSS)-phenanthraquinone doped poly methyl methacrylate (PQ/PMMA) was successfully fabricated via a one-pot free radical thermal polymerization technique by incorporating a Vi-POSS cross-linker into PQ/PMMA. The residual C=C bonds on the Vi-POSS branches after cross-linking significantly enhanced the holographic performance, achieving a high diffraction efficiency of 83% and a sensitivity of 0.49cmJ-1, while the cross-linked polymer matrix reduced volume shrinkage to 0.28% (compared to 64%, 0.33cmJ-1, and 0.39% for PQ/PMMA). Moreover, the Vi-POSS-PQ/PMMA sample exhibited excellent stability, with a bit error rate maintained at ∼0.5% over a broad holographic recording time range (3-13s), demonstrating its suitability for data storage applications by mitigating the effects of laser power fluctuations or system instability. Further experimental analysis confirmed the synthesis of a 3D cross-linked macromolecular network with Vi-POSS as the core. The residual C=C bonds in the Vi-POSS-PQ/PMMA matrix originated primarily from Vi-POSS, and a hexatomic cyclic -C-O-C- structure formed between Vi-POSS and PQ upon beam exposure. In conclusion, this study not only elucidates the microphysical and chemical mechanisms underlying the enhanced holographic performance of Vi-POSS-PQ/PMMA but also proposes a novel strategy to optimize storage stability for holographic data storage applications.

High-density storage of big data in the information age calls for higher data transmission rates. Holographic data storage technology, based on the principles of three-dimensional volume holographic recording and two-dimensional planar transmission, delivers an extremely high data transmission rate. Given the need for encoding two-dimensional data pages, spatial light modulators (SLMs) are employed for information encoding, and the modulation region of SLMs has become a key limiting factor for the data transmission rate of holographic data storage systems. However, to overcome the limitation that the limited imaging area of SLMs in holographic data storage fails to fully exploit the potential of this technology, this paper proposes an ultra-high-speed holographic data storage system based on extending data page size. The signal beams modulated by two digital micromirror devices (DMDs) are stitched and aligned through an optical system to achieve an expanded data page size. The reference beam is modulated using a mask to conserve the limited pixel resources of DMDs. Coupled with the 5:16 amplitude data encoding rule, the proposed system achieves an ultra-high data transmission rate of 20.06Gb/s.

After several centuries of development, photosensitive materials are being widely used in photography and videography. However, a material that possesses low shrinkage and can ensure high sensitivity is still elusive. Therefore, we have developed and designed a photosensitive material that maintains high sensitivity while exhibiting low shrinkage and excellent stability to address the growing demand for high-speed holographic data storage system in the big data era. A novel material, thiol-ene-phenanthrenequinone (PQ)-doped poly(methyl methacrylate) (PMMA), was developed by incorporating pentaerythritol tetra(3-mercaptopropionate) (PETMP) into a cross-linked PMMA network. Compared with traditional PQ/PMMA (~0.55 cm·J −1 ), the improved formulation demonstrated a four-fold increase in photosensitivity (~2.54 cm·J −1 ) and a drastically reduced response time (from ~70.93 s to ~7.57 s). More importantly, the material maintained a low photo-induced shrinkage factor of ~6.6‰. Practical testing in a collinear holographic storage system confirmed the capability of the material to record a single holographic data page within 1 s and maintain a bit error rate below 1%. Microscopic characterization revealed that the enhancement mechanisms involved the thiol-ene anti-Markovnikov addition reaction during exposure and a retardation effect during thermal polymerization, which increased the residual monomer concentration (from ~5% to ~11%) available for photochemical reactions. Furthermore, the cross-linked network improved the thermal stability of the PMMA matrix, evidenced by the increased decomposition temperature and glass transition temperature (T g ), without adversely affecting the volume stability. These findings indicate that the thiol-ene-PQ/PMMA material is a highly promising candidate for enabling fast high-density holographic data storage, potentially meeting the requirements of future servo-based collinear storage systems.

Current holographic data storage (HDS) systems mainly use amplitude and phase modulation for data encoding, while polarization is limited to multi-channel multiplexing, often causing operational difficulties and system complexity. To solve this, we propose a new, to the best of our knowledge, method that combines multiple polarization states into a single data page. Using polarization holography theory, we developed a reconstruction method capable of accurately reconstructing data pages with different polarization information. This method encodes data directly through multiple polarization states on one page. Decoding is simplified using a single 45° linear polarizer before the camera, enabling efficient distinction between different polarization states. Experiments show zero-error decoding for 2-, 3-, and 4-level polarization data pages. This research simplifies system design, reduces operation complexity, and expands HDS encoding dimensions, offering a new technical approach for practical high-density holographic storage.

Holographic data storage (HDS) offers a promising route toward high-capacity and high-throughput optical information storage. However, its achievable storage density is often limited by the dimensionality of the encoded optical field. Light inherently possesses multiple physical degrees of freedom, including amplitude, phase, and polarization, which provide an opportunity to substantially increase the information capacity of a single data page if they can be efficiently and reliably exploited. In this work, we investigate multidimensional information encoding and decoding in the HDS by fully utilizing these three fundamental properties of light. For encoding, a full three-dimensional modulation scheme is established by controlling the complex amplitude distributions of two orthogonal polarization states and employing a double-phase hologram strategy, which allows a single phase-only spatial light modulator to jointly encode amplitude, phase, and polarization information within the optical field. For decoding, a convolutional neural network, named TriDecode-Net, is designed to simultaneously retrieve three-dimensional information directly from diffraction intensity images. This approach enables synchronous recording and retrieval of multidimensional optical information, significantly increasing the information content of a single holographic data page compared with conventional holographic encoding approaches. Beyond data storage, the proposed multidimensional modulation and reconstruction framework also provides opportunities for optical encryption, anti-counterfeiting, high-capacity optical communication, and the generation and control of structured light fields.

In phase-modulated holographic storage, unequal interval phase encoding provides distinct diffraction intensity distributions between adjacent phases, which offers more discriminative features for convolutional neural networks. Numerous combinations of unequal-interval encoding schemes exist, and there is a lack of effective guidelines for their optimization. To address this, we propose an encoding design method based on phase difference interval optimization, which systematically regulates the distribution of phase differences to improve reconstruction performance. Simulation and experimental results demonstrate that the designed three-level and four-level encoding methods achieve the lowest phase reconstruction errors. Compared to the equal-interval encoding, the BER of the optimal three-level phase encoding (0, 43, 128) decreased by about 59%, while the BER of the optimal four-level phase encoding (0, 21, 85, 127) decreased by about 38%, validating the effectiveness and superiority of the proposed method. Furthermore, this approach has the potential to be extended to higher-level encoding, providing new insights for the encoding design of high-capacity holographic storage systems.

We present a hybrid multiplexing method for holographic optical storage that combines complex-amplitude encoding with polarization- and angle-based multiplexing to enhance storage density and capacity significantly beyond conventional approaches. By leveraging polarization holography, complex-amplitude data can be selectively recorded into orthogonal polarization channels. Furthermore, angular multiplexing is also applied to co-record multiple holograms at the same spatial location. During the reading process, each hologram can be selectively reconstructed under its specific Bragg and polarization conditions. Remarkably, despite exploiting these degrees, the reconstruction fidelity remains exceptionally high, with negligible degradation or crosstalk. This demonstrates a scalable route to high‑capacity, high‑fidelity holographic memories for next‑generation data‑intensive applications.

Holographic Memory Resolution® (HMR®) is a mind-based intervention without somatic movement used to treat individuals with conditions including depression, anxiety, post-traumatic stress disorder, and chronic pain. No studies on the lived experiences of HMR exist. This phenomenological study explored the perspectives of a subset of participants undergoing HMR in a larger open-label trial for chronic pain, dysphoric memory, and accompanying biopsychosocial symptoms. Eighteen participants were interviewed one-month post-HMR regarding their lived experiences. Thematic analysis revealed HMR facilitated: (1) Awareness of Coping Strategies and personal creation of a safe place, visualization of color, and use of a metaphorical lockbox to store traumatic memories, (2) Reframing of the Memory, (3) Relief and Release of Pain, and (4) Life Integration, which involved getting their voice back and feeling empowered to strengthen connections with others. Findings highlight HMR as an impactful mind-based tool to control chronic pain and provide relief for associated biopsychosocial symptoms.

Neural networks significantly outperform traditional methods in both decoding amplitude-, phase-, and polarization-encoded data pages and suppressing noise within them. However, the mechanism behind neural networks’ denoising capability remains not fully understood. We discover that zeroing channels can improve the reconstruction effect of the model. Consequently, this paper presents a method to locate the noise feature objectively from γ, the weights of the Batch Normalization (BN) layer. γ stands for the importance of the channel in the model and γ < 1 means the channel may contain noise feature. Through experiments, removing the channels that contained a higher proportion of these noisy features, the reconstructed data pages showed a ~2% improvement in Peak Signal-to-Noise Ratio (PSNR) compared to results obtained by directly outputting data without removing the noisy channels. It indicates that neural networks achieve efficient denoising of encoded data pages by adjusting the weight parameters of BN layers, thereby suppressing or enhancing specific channels.

We have developed a magnetic holographic memory using transparent bismuth-substituted rare-earth iron garnet as a next-generation optical memory. To realize this, a magnetic garnet with a large Faraday rotation angle and a moderately small extinction coefficient is required. In this study, we investigated the effect of Al or Ga substitution for the iron site of bismuth-substituted yttrium iron garnet (Bi/YIG) films on their magneto-optical properties. The Faraday rotation angle decreased with the amount of substitution, x, increase, for both Al- and Ga-substituted Bi/YIG, and a reversal of sign of rotation angle was only observed for Ga-substituted Bi/YIG, indicating a compensation composition. In the Al-substituted sample, due to small squareness, the residual Faraday rotation angle at zero magnetic field, |θR,res|, gradually decreased above x = 0.5, whereas in the Ga-substituted sample, the squareness ratio increased with increasing substitution up to x = 2.0, and thus showed a peak at x = 1.5. The Curie temperature and extinction coefficient were reduced with increasing substitution amount. As a result of a decrease in extinction coefficient, k, the high figure of merit, (|θR,res|/2πk) · λ was obtained around x = 1.5~1.9 for Ga and x = 2.1 for Al, while it was smaller than that of Bi/RIG we usually used.

Red Finance resources serve as historical witnesses to the economic governance and monetary struggles conducted by the Chinese people under the leadership of the Communist Party of China (CPC) during the revolutionary war era. They bear unique revolutionary spirit and Family-Country Sentiment. In the context of the era of digital survival, traditional physical archival memory faces the risks of communication rupture and semantic attrition. Based on the perspectives of cultural memory theory and media ecology, this paper proposes that "Digital Memory Reconstruction" is an inevitable path for the activation and value continuation of Red Finance resources. The article systematically elucidates the ontological logic of Red Finance digital memory reconstruction, which transforms discrete "archival memory" into interconnected "knowledge memory" and vivid "experiential memory" through digital technology. It deeply analyzes how this reconstruction process breaks spatio-temporal barriers, constructing a "bridge of memory" connecting history and reality, thereby achieving the contemporary inscription of Family-Country Sentiment—sublimating from the historical "saving the country through finance" to the new era's mission of "building a strong financial nation." The study concludes that by constructing a holographic digital memory field, a narrative-driven memory transmission mechanism, and a ritualized memory awakening strategy, we can effective resolve the "aphasia" dilemma in Red Finance education and establish the value identification and spiritual belonging of the youth in the new era towards the path of socialist financial development with Chinese characteristics.

The Bragg mismatch of volume holographic gratings enables high-density multiplexed recording, yet high-precision data reading demands strict Bragg matching of the reading light. This study focuses on investigating the tolerance of optical axis deviations of the recording objective lens during data reading in collinear holographic data storage system. Comprehensive analyses and comparisons were conducted on key performance metrics of reconstructed coded data pages, including normalized diffraction intensity, signal-to-noise ratio, and bit error rate. The experimental results indicate that the shift multiplexing interval of this system must be greater than 2 μm. During data reading, the servo precision needs to be maintained within ±200 nm; and the uncorrected system has a tilt angle tolerance of 1.3° for the storage medium. To mitigate the impact of medium tilt, a deep learning-based correction method was proposed. After correction, the system's tilt angle tolerance is enhanced to 3°, which is 2.3 times that of the uncorrected system. These findings provide reliable data support and crucial guidance for improving the storage performance of amplitude-modulated collinear holographic data storage devices and constructing specialized holographic storage servo systems.

Holographic data storage technology leverages the principles of laser interference to record two-dimensional data pages in a three-dimensional manner within a photosensitive medium. It boasts features such as high data storage capacity, long life, and fast data transmission rates. However, the non-uniform diffraction efficiency of the recording medium leads to distortion in the energy distribution of the reconstructed images. This issue impairs the training performance of the deep learning decoding network model, while also leading to a high bit error ratio when the traditional threshold method is adopted for decoding. To address this issue, this paper proposes a fixed-weight multi-level data page encoding method to ensure that data pages achieve a uniform energy distribution during the encoding phase. On this basis, an adaptive homomorphic filtering method is further introduced. This method is based on the uniform energy characteristics of fixed-weight data pages and reduces the variance of the energy distribution of reconstructed images. Subsequently, the filtered dataset is used to train a complex amplitude decoding convolutional neural network, while the known encoding information is utilized during the decoding process to directly mitigate the impact of uneven energy distribution. Ultimately, this approach reduces the bit error ratio of complex-amplitude data by over 60%. The proposed data page encoding approach and the adaptive homomorphic filtering method provide robust support for the further development of holographic storage and hold potential for cross-domain applications.

Holographic polymer-dispersed liquid crystal (HPDLC) gratings have great potential for applications in displays and data storage due to their exceptional optical modulation capabilities. Since their optical performance strongly depends on the phase separation between the polymer and liquid crystal (LC) induced by the photopolymerization, it is essential for improving the performance of HPDLC through the photokinetic aspect. In this work, we report (for the first time, to our knowledge) an enhanced HPDLC grating by using the reversible addition-fracture chain transfer (RAFT) agent. Experimental results show that a p-polarization diffraction efficiency (η) of 84% and a refractive index modulation (Δn) as high as 0.07 with the addition of RAFT are achieved in a 3-μm HPDLC grating. Significantly, comparing with the undoped grating, this corresponds to a near two-fold enhancement on η and an improvement of 62% on Δn. Moreover, we confirm that an increase in the size of LC-rich phase leads to a decreasing in the threshold voltage. We believe that the enhancement of HPDLC performance by RAFT provides an effective path to optimize the holographic photopolymer materials for uses of AR display and holographic data storage.

We propose what we believe to be a newly designed phase mask for holographic storage systems (HDS) and performed detection and evaluation of intensity-phase modulated multilevel signals. By adding phase signals to the non-signal regions where signals were not assigned in the conventional designed phase mask, we doubled the transfer rate and increased the recording density by approximately 1.1 times while maintaining the effect of crosstalk noise suppression.

In amplitude-modulated holographic storage, due to material inhomogeneity, optical system aberrations, and environmental interference, the recorded and read amplitude data pages often contain a large amount of random noise, leading to a decrease in the image signal-to-noise ratio (SNR). However, the traditional U-Net has a limited ability to handle random noise, particularly for low-SNR data pages, making it difficult to effectively enhance SNR. This paper proposes an improved U-Net named DRAMCU-Net (dilated residual attention and multi-scale convolution U-Net) for enhancing the SNR of holographic data storage images. DRAMCU-Net achieves multi-level feature extraction and attention focusing by introducing dilated residual attention blocks (DRABs) and utilizing multi-scale convolutional blocks (MS-Conv) instead of traditional convolutional blocks to efficiently capture feature information at different scales. Additionally, a dropout layer is employed to enhance the model's global robustness. Experimental results demonstrate that compared to the U-Net, the low-SNR data pages reconstructed by DRAMCU-Net achieve approximately 30% higher SNR.

Photopolymer PQ/PMMA, as a pivotal material in the field of holographic storage, demonstrates significant application potential owing to its advantages, such as straightforward preparation processes, cost-effectiveness, and tunable thickness. However, its practical application is still constrained by the need for further enhancement in key performance indicators, including diffraction efficiency, photosensitivity, and anti-aging properties. In this study, N-vinylpyrrolidone (NVP) is employed as a comonomer. By precisely controlling the doping ratio, we systematically investigate the influence mechanism of different NVP doping concentrations on the holographic performance of NVP-PQ/PMMA materials. Research indicates that the introduction of NVP effectively increases the vinyl concentration in the PQ/PMMA matrix, thereby directly generating photoproducts with PQ during the photoreaction process and further enhancing the photopolymerization process. Consequently, the holographic performance of the novel NVP-PQ/PMMA material is improved in a multi-faceted manner compared to ordinary PQ/PMMA. Specifically, the diffraction efficiency is enhanced by 1.93 times, the photosensitivity is increased by 1.64 times, the material uniformity is improved by 38%, and the light-induced shrinkage rate is reduced by 39%. Additionally, NVP-PQ/PMMA materials exhibit excellent stability and aging resistance in high-temperature accelerated aging experiments. Doping with a monomer of specific structure enhances the optical properties, providing broad adaptability for further research on PQ/PMMA photopolymer materials.

Lithium Niobate (LiNbO3, LN) crystals are multifunctional optical materials with excellent electro-optical, acousto-optical, and nonlinear optical properties, and their broad spectral transparency makes them widely used in electro-optical modulators, tunable filters, and beam deflectors. Near Stoichiometric Lithium Niobate (NSLN) crystals have a lithium to niobium ratio ([Li]/[Nb]) close to 1:1,demonstrate superior performance characteristics compared to composition lithium niobate (Congruent Lithium Niobate (CLN), [Li]/[Nb] = 48.5:51.5) crystals. NSLN crystals have a lower coercive field (~4 kV/mm), higher electro-optic coefficient (γ33 = 38.3 pm/V), and better nonlinear optical properties. This paper systematically reviews the research progress on preparation methods, the physical properties of LN and NSLN crystals, and their applications in devices such as electro-optical modulators, optical micro-ring resonators, and holographic storage. Finally, the future development direction of NSLN crystals in the preparation process (large-size single-crystal growth and defect control) and new electro-optical devices (low voltage deflectors based on domain engineering) is envisioned.