"The Era of 'Donut Light' is Coming: The 'Optical Vortex' Revolution Opens the Door to High-Density Communication"

Twisted Light Increases "Data Lanes"

Just as a vortex on the water's surface rotates while progressing, light can also become a "light vortex" when given a rotational movement (orbital angular momentum: OAM) in the direction of travel. Different modes of OAM can be multiplexed as separate "lanes," effectively expanding the amount of information that can be carried in the same bandwidth. This dream has been brought closer to reality not at a laboratory scale but at a "thin slice size" with the current achievement.Phys.org

What's New: Vortex Generation at Thickness "Several µm→Subwavelength"

Traditional light vortex generators required precision-engineered and bulky elements such as spiral phase plates, q-plates, spatial light modulators, and metasurfaces. The current method utilizes the inherent large birefringence of vdW materials, coupling the "spin" of circularly polarized light to "orbital angular momentum" (spin-orbit coupling) while reversing it. No nano-fabrication is needed. The vortex charge of ±2 was demonstrated with 8µm h-BN, and generation was successful even with 320nm MoS₂. Furthermore, with 26µm MoS₂, a conversion efficiency of 0.46 was achieved, approaching the theoretical limit of 0.5.Nature

Technically, when incident circularly polarized light (LCP/RCP) travels along the extraordinary axis of a crystal, the propagation components differ due to birefringence within the medium, converting it into a beam with opposite rotating circular polarization and OAM on the exit side. It's as if light entering a "hall of mirrors" has its phase twisted, reborn as a vortex beam with a donut-shaped dark spot.Phys.org

How "Small and Efficient" Is It?

The paper was published on August 18, 2025, in Light: Science & Applications. Efficiency was quantified as 0.30 for 8µm h-BN, 0.46 for 26µm MoS₂, and 0.09 for 320nm MoS₂. Numerical calculations further suggested that by shaping the incident beam into a Bessel beam, it might be possible to achieve both thinness and high efficiency, theoretically approaching near unity.Nature

The significance of this "thinness" is substantial. Traditionally, similar principles using lithium niobate (LN) or β-barium borate (BBO) required millimeter-scale thickness due to their small birefringence. With vdW materials, it's a few µm to subwavelength. This brings miniaturization, lightweight, and cost reduction into realistic reach.Nature

Horizons of Social Implementation: Communication, Quantum, Sensors

Light vortices can handle independent data paths for each mode (vortex charge), contributing to capacity expansion in OAM multiplexing for free-space, satellite, and fiber communications. The research team highlights "enhancing compatibility with existing communication technologies" and "efficiency improvement" as future focuses. The university media Pursuit also emphasizes "a path to fast and ultra-secure communication," with integration into satellite platforms and on-chip wiring in view.Phys.org

On the other hand, OAM is also important in quantum photonics. It holds potential for reducing fine processing of elements while delivering functionality in multidimensional quantum states (high-dimensional QKD, quantum routing) and noise-resistant encoding using vortex modes. This aligns with recent diverse developments in "twisted light" (e.g., new methods for skillfully designing the spatial distribution of vortices).

SNS Reactions: Rapid Spread and Voices of Expectation

Shortly after publication, Science X/Phys.org's official account posted the article on Threads. In the comments, expectations such as "The emergence of compact and affordable light vortex sources could accelerate new implementations for satellites and base stations" were prominent (※summary by the editorial team). Additionally, the article was featured in the trending section of the Chinese SNS aggregator "Buzzing," indicating high interest within the science and engineering community. Furthermore, the Lifeboat Foundation blog quickly picked up the key points of the paper (generation of ±2 vortex charge), boosting the topic's discussion.Lifeboat Foundation

The True Value and Limitations of "No Nano-Fab Required"

Advantages

• No Nano-Fabrication Required: Utilizing the material's inherent birefringence makes it easier to suppress manufacturing burdens and S/N degradation due to errors.Nature

• Ultra-Thin and Lightweight: Functions at 8µm to subwavelength. Advantageous for satellites, drones, and portable devices.Nature

• Signs of High Efficiency: 0.46 with 26µm MoS₂, approaching the theoretical limit of 0.5.Nature

Challenges

• Coupling and Alignment: Losses between free space and waveguides, suppression of crosstalk between OAM modes.

• Wavelength Band and Material Uniformity: Optical constants, defects, and domain irregularities of h-BN/various TMDs affect yield.

• Thermal and Power Resistance: Understanding thermo-optical degradation and damage thresholds during high-power operation.

• Standardization: Standards for OAM multiplexing, integration design with error correction and MIMO processing.

Research Positioning: Towards Optics Usable in "Three Fields" of Land, Sea, and Air

Methods for generating light vortices have diversified over the past decade, including metasurfaces, but solutions that combine being **"thin, cheap, and easy to mass-produce"** are rare. Generators based on vdW materials are promising candidates that challenge whether they can be brought down to the implementation field, beyond being "eye-catching devices" in laboratories. The paper succinctly organizes the basics of OAM, the limitations of existing methods, and why the large birefringence of vdW materials is effective.Nature

Future Points of Interest (Practical Perspective Checklist)

1. Fiber/Waveguide Integration: Can OAM modes be coupled into the chip without disruption?

2. Broadband Operation: Multi-wavelength operation utilizing the wide transmission band of h-BN and the anisotropy of TMDs.Nature

3. Mass Production Process: Scaling up and thickness control from CVD/mechanical exfoliation.

4. System Evaluation: Actual channel capacity, BER/OSNR, turbulence resistance in outdoor FSO.

5. Safety and Standards: Eye-safe design and compliance with peripheral standards for satellite/ground stations.
   
   
   

Sources (Main Information)

• General Explanation (August 19, 2025): Phys.org "Ultra-thin materials twist light into optical vortices…"Phys.org

• Original Paper (August 18, 2025): Light: Science & Applications "Spin-orbit coupling in van der Waals materials for optical vortex generation"Nature

• Official University Explanation: University of Melbourne Pursuit "We’re twisting light to move more data"

• Supplementary Information (Abstract DB): PubMed Listing Page

SNS and Web Reactions (Reference)

• Threads (Post by Science X/Phys.org)

• Trend Listing on Chinese SNS Aggregator "Buzzing"

• Introduction Post on Lifeboat Foundation Blog Lifeboat Foundation

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