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"Optical design"
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Materials Science and Technology of Optical Fabrication
Covers the fundamental science of grinding and polishing by examining the chemical and mechanical interactions over many scale lengths Manufacturing next generation optics has been, and will continue to be, enablers for enhancing the performance of advanced laser, imaging, and spectroscopy systems.
eBook
Artificial intelligence in optical lens design
Traditional optical design entails arduous, iterative stages that significantly rely on the intuition and experience of lens designers. Starting-point design selection has always been the major hurdle for most optical design problem, and different designers might produce different final lens designs even if using the same initial specification. Lens designers typically choose designs from existing lens databases, analyse relevant lens structures, or explore patent literature and technical publications. With increased processing capability, producing automated lens designs using Artificial Intelligence (AI) approaches is becoming a viable alternative. Therefore, it is noteworthy that a comprehensive review addressing the latest advancements in using AI for starting-point design is still lacking. Herein, we highlight the gap at the confluence of applied AI and optical lens design, by presenting a comprehensive review of the current literature with an emphasis on using various AI approaches to generate starting-point designs for refractive optical systems, discuss the limitations, and suggest a potential alternate approach for further research.
Journal Article
Opto-VLSI devices and circuits for biomedical and healthcare applications
\"The text comprehensively discusses the latest Opto-VLSI devices and circuits useful for healthcare and biomedical applications. It further emphasizes the importance of smart technologies such as artificial intelligence, machine learning, and the internet of things for the biomedical and healthcare industries\"-- Provided by publisher.
BOOK
Wide angle mini-LEDs combined with multifocal micro reflector cavity for thin portable device flashlight
LEDs employed in portable device flashes are Lambertian light sources, additional optical components such as Fresnel lenses and reflector cups must be incorporated to adjust the light distribution. This results in a need for a certain module thickness or high alignment precision. This paper introduces a modification in the packaging structure of mini-LEDs by employing a first optical design to create wide-angle mini-LEDs (WA mini-LEDs) with a light emission angle of 180°. A multi-focal micro-reflector cavity (MF-MRC) is included in the packaging process, thus enabling the achievement of a slim flash module. For the prototype design, measurements were conducted using WA mini-LEDs combined with a 2 mm height MF-MRC. The full width at half maximum can be reduced to 56° while maintaining a uniformity of up to 60% across all measurement points. Additionally, the center illuminance is 3.24 times higher compared to Lambertian mini-LED light sources.
Journal Article
High-Precision Construction of Off-Axis Multi-Reflective Systems for a Single Field of View Based on a Stable Initialization Seed Curve Extension Algorithm
Freeform optical design is regarded as a key approach to overcoming the performance limits of traditional imaging systems. However, the existing Seed Curve Expansion (SCE) algorithm has two major limitations. First, the initial and ideal image points are selected randomly, causing unstable optical performance and low construction accuracy, especially under finite object distance and non-paraxial incidence. Multiple trials are often needed, reducing efficiency and repeatability. Second, the algorithm cannot constrain aperture, focal length, or geometry; thus, despite good imaging quality, the final system parameters often deviate from design requirements, limiting engineering applicability. To address these issues, this work proposes a Stable Initialization Seed Curve Expansion (SI-SCE) algorithm based on ray tracing and Fermat’s principle. The method accurately calibrates the initial point and the ideal image point, eliminating uncertainties caused by randomness. A virtual auxiliary surface strategy is introduced to achieve high-precision freeform construction under finite object distance. In addition, a parameter constraint mechanism is embedded in the algorithm, enabling the designed off-axis multi-reflective freeform system to directly meet specified requirements on pupil diameter, focal length, and geometric size. The feasibility of the SI-SCE algorithm was demonstrated by designing a freeform off-axis three-mirror imaging system with a rectangular 6°×6° field of view and a moderate F-number. The final system features an F-number of 3.4 and an entrance pupil diameter of 60 mm. It achieves diffraction-limited performance across the Visible–NIR 0.38−2 μm wavelength range.
Journal Article
Light Guide Layer Thickness Optimization for Enhancement of the Light Extraction Efficiency of Ultraviolet Light–Emitting Diodes
Consider material machinability and lattice mismatch sapphire as substrates for the ultraviolet-C light-emitting diodes (UV-C LEDs) are commonly used, but their high refractive index can result in the total internal reflection (TIR) of light whereby some light is absorbed, therefore caused reducing light extraction efficiency (LEE). In this study, we propose a method to optimize the thickness of a sapphire substrate light guide layer through first-order optical design which used the optical simulation software Ansys SPEOS to simulate and evaluate the light extraction efficiency. AlGaN UV-C LEDs wafers with a light guide layer thickness of 150–700 μm were used. The simulation proceeded under a center wavelength of 275 nm to determine the optimal thickness design of the light guide layer. Finally, the experimental results demonstrated that the initial light guide layer thickness of 150 μm the reference output power of 13.53 mW, and an increased thickness of 600 um resulted in output power of 20.58 mW. The LEE can be increased by 1.52 times through light guide layer thickness optimization. We propose a method to optimize the thickness of a sapphire substrate light guide layer through first-order optical design. AlGaN UV-C LEDs wafers with a light guide layer thickness of 150–700 μm were used. Finally, the experimental results demonstrated that the LEE can be increased by 1.52 times through light guide layer thickness optimization.
Journal Article
Computational Imaging in Dual-Band Infrared Hybrid Optical System with Wide Temperature Range
The special dispersion and temperature characteristics of diffractive optical element (DOE) make them widely used in optical systems that require both athermalization and achromatic aberrations designs. The multi-layer DOE (MLDOE) can improve the diffraction efficiency of the overall broad waveband, but its diffraction efficiency decreases with changes in ambient temperature. When the ambient temperature changes, the micro-structure heights of MLDOE and the refractive index of the substrate materials change, ultimately affecting its diffraction efficiency, and, further, the optical transform function (OTF). In this paper, the influence of ambient temperature on the diffraction efficiency of MLDOE in a dual-infrared waveband is proposed and discussed, the diffraction efficiency of MLDOE caused by ambient temperature is derived, and a computational imaging method that combines optical design and image restoration is proposed. Finally, a dual-infrared waveband infrared optical system with athermalization and achromatic aberrations corrected based on computational imaging method is designed. Results show that this method can effectively reduce the diffraction efficiency of MLDOE by ambient temperature and improve the imaging quality of hybrid optical systems.
Journal Article
Compact Magnetless Optical Isolator using Two Coupled Microcavities with Time-Modulation
It is shown how time-modulating the refractive index of two coupled microcavities with a 90 degree phase shift between them leads to non-reciprocal wave propagation. The cavities are implemented as defects in a one-dimensional photonic crystal. The ratio of forward to backward power transmission can be as high as 25 dB with experimentally realizable modulation frequencies and amplitudes. Further, it is demonstrated how a simple passive filter can remove modulation sidebands.
Conference Proceeding