Author: raoam488

Researchers have developed innovative multifunctional metasurfaces that can simultaneously focus vortex beams and multiplex data, marking a significant advancement in optical communication technology. This breakthrough leverages a dual-frequency bilayer Pancharatnam–Berry phase unit cell, demonstrating enhanced data transmission efficiency within the terahertz (THz) frequency range.

The demand for higher data capacity and integration density is pushing the limits of current communication technologies. Traditional single-function metasurfaces, which manipulate electromagnetic waves, are limited in their capabilities. To overcome this, researchers are exploring more advanced designs, leading to multifunctional and multiplexing metasurfaces. The newly developed unit cell, characterized by its sub-wavelength thickness, can act as a fundamental component for creating ultrathin and compact metasurfaces capable of manipulating wavefronts, improving optical communication protocols.

Operating at two distinct frequencies, 0.83 THz and 1.72 THz, the bilayer metasurface achieves high cross-polarization conversion ratios of 86.3% and 88.5% respectively. This enhanced performance is crucial for generating focused vortex beams and enabling multichannel orbital angular momentum (OAM) multiplexing.

Vortex beams are increasingly important for data encoding because of their unique topological charge, representing angular momentum. By using segmented designs, these new metasurfaces can generate multiple OAM beams simultaneously, boosting both data capacity and the quality of optical communication. Three multifunction metasurface designs were tested and successfully demonstrated the focusing of vortex beams at sub-wavelength scales and across multiple frequencies. These multichannel capabilities are vital for integrating these technologies into sophisticated photonic systems.

The research, supported by several leading institutions and grants, highlights a collaborative effort to advance optical technology. Adjustments in the unit cell structure allow for customized designs that are compatible with different wavelengths and polarization states, ensuring optimal performance.

These innovations are expected to have broad applications, from consumer electronics to telecommunications, enhancing data transmission efficiency to meet the growing demands of the digital age. Data multiplexing capabilities increase transmission capacity without requiring additional physical infrastructure.

Practical demonstrations of vortex metalenses have shown efficient focusing and manipulation of OAM capacities. These designs underscore the importance of such advancements for the future of optical communication. The findings suggest substantial potential for larger-scale applications and improvements across various fields.

By increasing spectral efficiency and transmission capacity, these metasurface technologies are positioned to play a major role in the optical communication sector. Their ability to adapt to specific operational frequencies and polarization dependencies makes them well-suited to address the urgent need for high-capacity data systems.

These findings emphasize the value of ongoing innovation in optical technologies and offer pathways for the practical application of these devices across diverse fields. Researchers are continuing to refine the capabilities for focusing and manipulating optical beams, emphasizing the critical role of this research in the ongoing evolution of high-capacity optical communications and integrated optical systems.

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Freeform optical elements are receiving increased attention for illumination applications due to their capacity to tailor light output precisely, enhancing visual aspects and energy efficiency. While software tools for designing freeform surfaces have been available, it is the recent integration of these capabilities into comprehensive illumination design software that marks a significant advancement. This integration makes the design and application of reflective and refractive freeform optical elements a more accessible and practical undertaking for numerous illumination applications and designers.

Synopsys has recently launched the Freeform Designer as part of its LightTools illumination design software, incorporated within the Advanced Design Module. This tool facilitates the calculation of freeform reflective and refractive surfaces based on specified light distribution targets, source angle characteristics, and geometric parameters. The fundamental principle behind the design process is the mapping of the source’s angular light distribution to a desired target distribution, which can be either angular or spatial depending on the application requirements. By understanding the light distribution on the freeform surface in relation to position and incoming angle, the surface can be shaped to ensure the outgoing light achieves the intended target distribution, whether directed onto a specific surface or within a defined angular space. Although conceptually straightforward, the implementation of this mapping can be complex, particularly without symmetrical conditions. Nonetheless, the approach is effective in generating surfaces applicable for both simple and intricate target distributions.

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Optical engineers have developed a novel automated design method for creating advanced freeform optical systems. This new approach streamlines the complex process of designing these systems, which are crucial for high-performance imaging applications.

The method begins by generating a range of traditional coaxial spherical lens configurations as a starting point. In the first phase, these configurations are systematically varied based on optical path distributions. Mathematical formulas are employed to calculate key parameters of these systems, such as curvature radii and surface distances, laying the foundation for further design modifications.

Moving beyond conventional designs, the second phase introduces innovative structural changes. Each optical surface within the initial coaxial systems is deliberately tilted and repositioned. This transformation leads to the creation of non-coaxial systems with diverse configurations, including off-axis designs. This step is crucial for exploring a broader design space and creates systems tailored for specific performance requirements.

The third phase marks a shift to freeform optics. Building upon the non-coaxial systems generated, the optical surfaces are reshaped into complex freeform surfaces. This is achieved using a point-by-point construction method, carefully adjusting surface shapes to correct for optical path differences introduced in the previous tilting phase. By employing polynomial functions to represent these intricate surfaces, this ensures the system maintains high optical performance.

To further refine the designs, the fourth phase focuses on enhancing image quality. An iterative optimization process is applied, repeatedly adjusting the freeform surfaces based on ray tracing analysis. This method ensures continuous improvement of the image quality. Furthermore, the image plane itself is also finely adjusted for optimal tilt, maximizing the final image sharpness.

In the final phase, the performance of each designed system is rigorously evaluated using industry-standard metrics such as spot size, modulation transfer function, and wavefront error. Only the designs meeting stringent quality criteria are presented as final outputs, allowing optical designers to select the most suitable solution for their specific application. This automated method promises to significantly accelerate the design process for sophisticated freeform optical systems and expand the possibilities for advanced optical technologies.

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Azthena, an information platform, has issued a notice to users regarding the limitations and terms of using its service. The platform advises users that while content is edited and approved, responses may still be inaccurate and require verification from relevant suppliers or authors. Specifically highlighted is the platform’s inability to offer medical advice, stressing that users seeking health information must consult qualified medical professionals. Furthermore, Azthena clarifies that user questions, excluding email addresses, will be shared with OpenAI and kept for 30 days according to OpenAI’s privacy policies. Users are also cautioned against submitting questions containing sensitive or confidential information. For a comprehensive understanding of the terms, users are directed to the full Terms & Conditions document available via a provided link.

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Researchers have developed a new approach to designing freeform optical systems, focusing on understanding and correcting aberrations, which are imperfections that distort images. The study categorizes optical systems based on their symmetry, primarily concentrating on systems with one plane of symmetry, as they are most common.

The research team utilizes a detailed mathematical method to describe and analyze aberrations in these systems. They employ a series of equations to represent the deviations of light rays from their ideal paths, breaking down these deviations into different orders of aberrations, similar to how standard lens aberrations are understood. This approach allows for the description of aberrations in systems lacking rotational symmetry, unlike traditional methods.

The scientists consider optical systems as a sequence of reflective or refractive surfaces. They model each surface mathematically using power series, acknowledging that in systems with one plane of symmetry, certain terms in these series disappear. To track how light rays interact with each surface, they introduce “ray mapping functions,” which are also expressed as power series. These functions describe where a ray, defined by its starting point and direction, intersects each optical surface.

The core of the method relies on Fermat’s principle, which states that light rays travel along paths that minimize the optical path length. Applying this principle leads to a set of differential equations that govern the behavior of light within the optical system. The researchers use a power series method to solve these equations, allowing them to determine the coefficients in their mathematical descriptions of surfaces, ray mappings, and aberrations.

The design process is broken down into steps. First, the basic layout of the optical system is defined, including the number and type of optical components. Then, the differential equations are formulated and solved in stages. Initially, a non-linear system of equations is solved to define the basic optical properties. Subsequently, linear systems of equations are solved order by order to refine the system design by minimizing or eliminating specific aberrations. Weighting factors based on system specifications like entrance pupil diameter and field of view are incorporated to ensure practical performance.

This deterministic design method aims to provide a “first time right” solution for freeform optical systems. It provides a starting point that accurately describes the optical system and its performance, which can then be further refined using conventional optical design software optimization techniques. The method also includes an analytical ray-tracing evaluation, allowing designers to interpret the system’s behavior and explore design alternatives. The researchers emphasize that this approach offers a direct and efficient way to design complex freeform optical systems and evaluate their imaging quality.

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Synopsys has released version 10.8 of its CODE V® software, designed for the optimization, analysis, and tolerancing of image-forming optical systems and free-space photonic devices. The latest iteration of the software provides enhanced support for the design of high-performance asymmetric and freeform optical systems. Algorithmic improvements within version 10.8 enable highly accurate computations of optical system parameters and allow for precise parameter control during the design optimization process. Furthermore, CODE V 10.8 introduces extended aspheric lens formulations, new options for customizing workflows, and an expanded materials library for designers. The latest data is available for download at https://optics.synopsys.com/codev/.

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Demand for specialized optical components designed for ultrafast lasers has surged in recent years, driven by the increasing applications of these advanced laser systems. Unlike optics used in continuous-wave or longer-pulse lasers, components for ultrafast lasers, particularly those operating in the femtosecond range, require stringent dispersion specifications. This is especially critical for pulses shorter than 100 femtoseconds, where the broad spectral bandwidth poses significant challenges in coating design and manufacturing.

A key challenge in developing these advanced optics is optimizing their laser damage threshold (LDT) while meeting all optical performance requirements. Achieving high LDT often necessitates a delicate balance in selecting coating materials and managing the electric field distribution within the multilayer coating structure. Researchers are actively exploring innovative material combinations and design strategies. One promising approach under investigation involves a three-material system, demonstrated through the development of a broadband mirror with low group delay dispersion, centered at 920 nanometers.

The performance and longevity of laser optics are influenced by potential damage at coatings, interfaces, and the substrate. Focusing on thin-film coatings, three primary damage mechanisms are identified. Thermal damage, primarily observed in continuous-wave lasers, arises from absorption and heat conduction within the coating layers. Defect-induced damage, more pertinent to pulsed lasers that are not ultrafast, is linked to the presence of particles and contaminants. Finally, electronic damage, the dominant mechanism in ultrafast laser systems, is highly sensitive to the electric field distribution inside the multilayer coating and the ultraviolet (UV) absorption properties of the coating materials. The threshold fluence, a critical parameter indicating the damage resistance of a thin film, can be related to the laser pulse duration and the coating material’s UV absorption edge through a specific equation.

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Bedford, Massachusetts and Cambridge, England, March 2, 2016 – Polatis, a leader in fiber layer switching solutions, has launched its Series 7000 Optical Circuit Switch (OCS), boasting the industry’s highest port count for an all-optical cross connect. The new switch is a fully non-blocking all-optical matrix switch offering up to 384×384 fiber ports and is available immediately.

The Series 7000 is designed to be space-efficient, occupying only 4RU of rack height, which Polatis claims packs 20% more capacity into 40% less space compared to alternative solutions. It utilizes Polatis’ DirectLight optical switch technology, aiming for superior performance and reliability.

Nick Parsons, Chief Technology Officer at Polatis, stated that the company doubled the maximum matrix size based on customer demand, while maintaining optical performance. He added that the Series 7000 expands their product range to offer a broader selection of dynamic fiber cross-connect solutions with open, programmable interfaces for modern software-defined networks.

Polatis highlights the energy efficiency of the Series 7000 OCS, stating it consumes about as much power as a lightbulb, yet it can route over 3.7Pb/s of optical traffic with up to 9.6Tb/s capacity per fiber. The switch allows for rapid reconfiguration in milliseconds, regardless of signal characteristics. Based on DirectLight technology, it keeps control and data planes separate, enabling path pre-provisioning and transparent connections without needing to analyze fiber traffic. Additional features include optical power monitoring, variable attenuation, and autonomous optical layer protection switching.

The Series 7000 OCS is designed for integration with Software Defined Network (SDN) controllers, supporting open SDN protocols like OpenFlow, NETCONF, and RESTCONF. Polatis emphasizes its embedded interfaces for seamless SDN integration, and highlights being the first all-optical switch vendor to release a NETCONF interface with YANG models for transport SDN and network functions virtualization (NFV) management.

Polatis has partnered with Quali to integrate the platform with cloud orchestration software, aiming to enable automated fiber layer provisioning and deployment for system integration testing.

Gerald Wesel, CEO of Polatis, commented that the Series 7000 and its software features facilitate flexible, dynamic optical networks at scale. He pointed out the potential for reduced operational costs, improved service quality and speed, and enhanced data center server utilization through dynamic resource allocation. Wesel emphasized that Polatis now offers a comprehensive range of optical switches from 4×4 to 384×384, coupled with software features to suit various application needs.

Polatis specializes in low-loss all-optical switching solutions for fiber-layer management, including provisioning, protection, monitoring, reconfiguration, and testing. The company states its DirectLight optical matrix switch technology is field-proven, scaling from 4×4 to 384×384 ports, and suitable for telecommunications, data centers, government, test, and video networks.

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Scientists in Israel have developed a novel and cost-effective method for creating diffractive optical elements (DOEs), which are crucial components for shaping light in advanced optical systems. Unlike traditional lenses, DOEs can manipulate light in complex ways but typically require expensive and intricate manufacturing. Researchers at The Technion achieved this breakthrough by combining 3D printing with a liquid immersion technique using water and glycerol, a common food additive.

The two-step process begins with 3D printing the desired shape of the optical element, such as a phase mask. This 3D-printed mold is then used to cast a transparent polymer DOE element. The key innovation lies in immersing this element within a small chamber filled with a mixture of water and glycerol. By adjusting the ratio of water to glycerol, scientists can precisely fine-tune the optical properties of the DOE.

This liquid immersion approach offers several advantages. It allows for the creation of DOEs with larger features – at the scale of tens of microns instead of tens of nanometers – meaning less precise and thus more affordable 3D printers can be used. Professor Yoav Shechtman, a biomedical engineer at the Technion, highlighted that modern additive-manufacturing (3D printing) technology was essential for enabling the creation of these non-standard optical elements efficiently. His team, including graduate student Reut Orange-Kedem, discovered that immersing the DOE in a liquid with a refractive index similar to the solid element effectively increases the element’s axial size and tolerance for manufacturing errors.

Following the casting of the polymer element, it is bonded to a silica substrate and placed within a specially designed chamber. After removing any air bubbles, the chamber is filled with the water-glycerol mixture. The ability to easily switch and adjust the liquid mixture allows for adaptable optical performance. The researchers successfully tested their liquid-immersion DOE in 3D single-molecule localization microscopy of fluorescently labeled cells.

The reusability of the 3D-printed mold and the potential to create multiple designs from a single mold make this technique attractive for optics manufacturers. Professor Shechtman suggests that while applicable to various transparent optical elements, the method is particularly impactful for creating unconventional optical elements like DOEs and those with specialized geometries. The team hopes to see broad adoption of this technique in both academic and industrial settings and aims to further explore more complex optical designs and integration into biomedical imaging systems.

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