Stories with Tag Lens Design

• Show HN: Torch Lens Maker – Differentiable Geometric Optics in PyTorch

  permalink

  Posted: 2025-03-21 13:29:11

  Verbose tl;dr

  Torch Lens Maker is a PyTorch library for differentiable geometric optics simulations. It allows users to model optical systems, including lenses, mirrors, and apertures, using standard PyTorch tensors. Because the simulations are differentiable, it's possible to optimize the parameters of these optical systems using gradient-based methods, opening up possibilities for applications like lens design, computational photography, and inverse problems in optics. The library provides a simple and intuitive interface for defining optical elements and propagating rays through the system, all within the familiar PyTorch framework.

  The Hacker News post titled "Show HN: Torch Lens Maker – Differentiable Geometric Optics in PyTorch" introduces a new Python library called torchlensmaker. This library leverages the automatic differentiation capabilities of PyTorch to simulate and optimize complex optical systems. It provides a framework for defining optical elements, such as lenses and mirrors, and tracing light rays through these elements using differentiable ray tracing. This differentiability is the key innovation, enabling gradient-based optimization techniques to be applied to the design and analysis of optical systems.

  The library offers a variety of features for modeling optical phenomena. Users can define different types of lenses, including spherical and aspherical lenses, specifying parameters like their curvature, refractive index, and aperture. Mirrors can also be incorporated into the system, allowing for the simulation of reflective optics. The library supports tracing both meridional and skew rays, providing a comprehensive approach to light propagation analysis. It handles refraction and reflection at optical interfaces according to Snell's law and the law of reflection, respectively.

  The core functionality revolves around the differentiable ray tracing engine. This engine calculates the paths of light rays as they interact with the defined optical elements, taking into account the parameters of each element. Crucially, these calculations are performed in a way that preserves the differentiability of the system. This means that changes in the optical parameters, such as the curvature of a lens, will result in corresponding changes in the ray paths that can be computed using automatic differentiation. This allows for the application of gradient-based optimization algorithms to tasks like lens design, where the goal might be to find the optimal lens shapes and configurations to achieve a desired optical performance.

  The potential applications of this library are extensive, ranging from the design of camera lenses and telescopes to the development of new optical devices. The ability to use gradient-based optimization offers a powerful tool for exploring complex optical designs and potentially discovering novel solutions. The use of PyTorch as the underlying framework provides benefits such as GPU acceleration and access to a rich ecosystem of tools and resources. torchlensmaker empowers researchers and engineers to model, analyze, and optimize optical systems with a high degree of flexibility and precision, leveraging the power of differentiable programming.

  • PyTorch
  • Geometric Optics
  • Differentiable Programming
  • Lens Design
  • Simulation
  • Physics Engine
  • computer graphics
  • optics
  • ray tracing
  • GPU acceleration
  • Python
  • Open Source
  • Scientific Computing

  Summary of Comments ( 13 )
  https://news.ycombinator.com/item?id=43435438

  Verbose tl;dr

  Commenters on Hacker News generally expressed interest in Torch Lens Maker, praising its interactive nature and potential applications. Several users highlighted the value of real-time feedback and the educational possibilities it offers for understanding optical systems. Some discussed the potential use cases, ranging from camera design and optimization to educational tools and even artistic endeavors. A few commenters inquired about specific features, such as support for chromatic aberration and diffraction, and the possibility of exporting designs to other formats. One user expressed a desire for a similar tool for acoustics. While generally positive, there wasn't an overwhelmingly large volume of comments.

  The Hacker News post discussing Torch Lens Maker, a differentiable geometric optics library in PyTorch, has generated several comments exploring its potential applications and limitations.

  One commenter expresses excitement about the possibilities, particularly for tasks like optimizing freeform lens designs and simulating complex optical systems. They envision using the library to design lenses for virtual and augmented reality applications, where precise control over light propagation is crucial. This commenter also sees potential in using the library for scientific applications like designing microscopy systems or telescopes.

  Another commenter raises a practical concern about the computational cost of differentiable rendering for complex optical systems. They suggest that while the concept is intriguing, the computational burden could become prohibitive for real-world scenarios involving a large number of lenses or intricate geometries. This concern highlights a potential limitation of the library for certain applications.

  Further discussion revolves around the potential use cases of the library beyond traditional lens design. One commenter suggests its applicability in areas like computational photography, where simulating the effects of different lenses can be valuable. Another commenter mentions the possibility of using it for educational purposes, providing a visual and interactive way to understand the principles of geometric optics.

  A technically-oriented comment delves into the underlying implementation details, questioning the use of PyTorch's autograd functionality for gradient calculations. They suggest that a dedicated ray tracing engine might be more efficient for this specific application, as PyTorch's automatic differentiation might introduce unnecessary overhead.

  Finally, a commenter expresses interest in exploring the possibility of integrating Torch Lens Maker with other differentiable physics engines to create more comprehensive simulations. This idea suggests a broader application of the library within the realm of scientific computing and simulation.

  Overall, the comments reflect a general interest in the potential of Torch Lens Maker, while also acknowledging the practical challenges and limitations that need to be considered. The discussion highlights the diverse range of potential applications, from traditional lens design and computational photography to scientific research and education. Furthermore, the comments delve into some of the technical aspects of the library, suggesting potential areas for improvement and future development.

• Optical Fresnel zone plate flat lens: colored photoresist through I-line stepper

  permalink

  Posted: 2025-01-17 13:40:33

  Verbose tl;dr

  Researchers have fabricated a flat, diffraction-based lens using a single layer of colored photoresist patterned via conventional I-line stepper lithography. By varying the photoresist's absorbance at different wavelengths, they created a Fresnel zone plate structure that focuses different colors of light at different focal lengths. This chromatic aberration is typically a drawback, but here it's exploited to produce color filtering and full-color imaging onto a single image sensor, eliminating the need for complex and bulky Bayer filters. This low-cost, readily-scalable fabrication method opens new possibilities for compact, multispectral imaging systems.

  This Nature Light: Science & Applications article details the fabrication and characterization of a novel flat lens based on the Fresnel zone plate principle, achieved using a conventional I-line stepper lithography process and a colored photoresist. Traditional Fresnel zone plates, while offering potential advantages in terms of compactness and cost-effectiveness compared to conventional refractive lenses, suffer from chromatic aberration due to their diffractive nature. Different wavelengths of light focus at different distances, resulting in blurry images and limiting their applicability, especially for full-color imaging. This research overcomes this limitation by leveraging the wavelength-dependent absorption properties of a commercially available colored photoresist.

  The researchers meticulously designed a multi-level Fresnel zone plate structure. By carefully tuning the exposure dose during the lithography process, they controlled the depth of the etched features within the colored photoresist. Crucially, the colored photoresist exhibits varying degrees of absorption for different wavelengths of light (specifically, the I-line wavelength used for lithography and the target wavelengths for imaging - blue, green, and red). This differential absorption enables the creation of distinct zone profiles for each color channel within a single lens element. The fabrication process involves multiple exposures at optimized doses, effectively creating a superimposed set of Fresnel zone plates tailored for different wavelengths within the same photoresist layer.

  The resulting lens demonstrates a remarkable ability to focus blue, green, and red light at the same focal plane, effectively mitigating chromatic aberration. The authors rigorously characterize the lens performance through experimental measurements and simulations, showcasing the achieved focusing efficiency and the reduction in chromatic focal shift. They demonstrate a significant improvement in the polychromatic focusing efficiency compared to conventional single-material Fresnel zone plates. The use of a standard I-line stepper for fabrication underscores the potential for cost-effective mass production of these chromatic-aberration-corrected flat lenses. This approach offers a promising pathway towards integrating compact and high-performance optical elements into a wide range of applications, including imaging, sensing, and virtual/augmented reality devices, without resorting to complex and expensive fabrication techniques. The researchers suggest that further optimization of the photoresist formulation and the lithography process could lead to even better performance and broader applicability of this innovative flat lens technology.

  • optics
  • Fresnel Zone Plate
  • Flat Lens
  • Photolithography
  • I-Line Stepper
  • Colored Photoresist
  • Nanofabrication
  • Microoptics
  • Diffractive Optics
  • Imaging
  • Lens Design
  • Optical Materials
  • photonics

  Summary of Comments ( 5 )
  https://news.ycombinator.com/item?id=42737401

  Verbose tl;dr

  HN commenters discuss the practicality and implications of the Fresnel zone plate lens fabrication method described in the linked Nature article. Some express skepticism about its real-world applicability due to chromatic aberration and limited resolution, pointing out that current multi-element lens systems already address these issues effectively, particularly for photography. Others find the technique interesting for specialized applications like microscopy or lithography where simplicity and cost-effectiveness might outweigh the drawbacks. The potential for customizing the focal length and numerical aperture for specific wavelengths is also highlighted as a potential advantage. A few commenters delve into the technical details of the fabrication process, questioning aspects like alignment precision and the impact of resist thickness variations. Overall, the consensus seems to be that while the approach isn't revolutionary for general-purpose optics, it offers intriguing possibilities for niche applications.

  The Hacker News post titled "Optical Fresnel zone plate flat lens: colored photoresist through I-line stepper," linking to a Nature article about creating flat lenses using colored photoresist, has a modest number of comments, generating a brief but focused discussion.

  Several commenters focus on the practical implications and limitations of this technology. One commenter questions the scalability of the fabrication process, specifically regarding the use of an I-line stepper, which they believe might limit the achievable resolution and therefore the potential applications. Another user responds by agreeing with the limitations of I-line steppers but suggesting that more modern and higher resolution photolithography techniques could be employed to overcome this hurdle. This exchange highlights the manufacturing challenges in moving this technology from lab demonstration to widespread adoption.

  Another commenter points out the chromatic aberration inherent in Fresnel lenses, implying that while the research is interesting, this fundamental optical limitation would need to be addressed for broader applicability. They question the practical advantage over existing lens technologies if color correction remains a problem.

  One commenter draws a parallel between this research and previous work on diffractive optics, suggesting that the novel aspect here lies primarily in the use of colored photoresist. They question whether this approach offers significant advantages over other methods for creating diffractive elements.

  Finally, one commenter makes a more general observation about the nature of academic research, suggesting that the title of the paper might oversell the practical significance of the findings. They argue that the research primarily demonstrates a fabrication technique rather than a revolutionary new type of lens.

  In summary, the comments on Hacker News reflect a cautious but interested response to the research. They acknowledge the novelty of the fabrication technique but also raise important questions about scalability, chromatic aberration, and overall practicality compared to existing lens technologies. The discussion is grounded in a realistic understanding of the challenges involved in translating academic research into commercially viable products.