Article
Optics
Honghao Zhang, Satoshi Hasegawa, Haruyoshi Toyoda, Yoshio Hayasaki
Summary: Feedback control and computer-generated holograms enable automatic compensation for imperfections and long-term stability in parallel focusing. Demonstrating success in single-shot 3D fabrication in transparent glass proves the effectiveness of this parallel laser processing method.
OPTICS AND LASERS IN ENGINEERING
(2022)
Article
Optics
Satoshi Hasegawa, Mizuki Kato, Yoshio Hayasaki
Summary: A holographic UV nanosecond laser processing technique was used to fabricate a through hole in a polyimide film. The UV laser was modulated into a Bessel beam by a diffractive axicon displayed on a spatial light modulator, resulting in improved light efficiency and simplified optical setup. The proposed method reduced the number of pulse shots required for through-hole fabrication and implemented adaptive optics to compensate for aberrations.
APPLIED PHYSICS B-LASERS AND OPTICS
(2023)
Article
Optics
Jin Wang, Shufeng Sun, Honghao Zhang, Satoshi Hasegawa, Pingping Wang, Yoshio Hayasaki
Summary: This novel holographic femtosecond laser parallel processing method utilizes the fractional Fourier transform to increase flexibility and available space for processing, with computer-generated holograms and an iterative algorithm for uniformity and efficiency. By adjusting the femtosecond laser beam using a spatial light modulator, complex microstructures can be processed in parallel, with the zero-order beam spot defocused or utilized to improve laser energy utilization for various structures.
OPTICS AND LASERS IN ENGINEERING
(2021)
Article
Nanoscience & Nanotechnology
Feifei Wang, Lan Jiang, Changji Pan, Zhipeng Wang, Yiling Lian, Qingsong Wang, Wenpan Tao, Jingya Sun
Summary: Holograms hidden inside transparent materials are important for information encryption storage. By using double-pulse femtosecond laser processing, holograms can achieve improved imaging quality, and the effect and mechanism of self-trapped excitons (STEs) on the ablation have been systematically studied.
Article
Optics
Satoshi Hasegawa, Yoshio Hayasaki
Summary: This paper demonstrates an adaptive optics technique based on convolutional neural network for femtosecond laser processing, continuously predicting and compensating aberrations to reduce wavefront error in the system.
OPTICS AND LASERS IN ENGINEERING
(2021)
Article
Optics
Jin Wang, Fengyun Zhang, Xi Wang, Yadi Wang, Jing Shao, Pingping Wang, Sunfeng Sun
Summary: In this paper, a zooming relationship for holographic parallel laser foci with the fractional Fourier transform is revealed and optimized. This relationship allows for accurate control of microfabrication of structures and micropatterning of material surfaces. The experiments verify that the consistency between parallel microstructures is determined by sampling intervals and fractional orders. The fractional holographic parallel laser multifocus processing method shows great potential for processing multilayer structural materials and complex surface topography.
OPTICS AND LASER TECHNOLOGY
(2023)
Article
Chemistry, Multidisciplinary
Qinhui Yang, Yu Zhao, Wei Liu, Jingwen Bu, Jiahui Ji
Summary: This paper addresses the problems of slow speed, low reconstruction quality, and high hardware resource consumption in real-time high quality full-color 3D display. It proposes the Taylor Rayleigh-Sommerfeld diffraction point cloud grid algorithm (TR-PCG), which performs Taylor expansion on the radial value of Rayleigh-Sommerfeld diffraction in the hologram generation stage and modifies the data type to effectively accelerate the calculation speed and ensure the reconstruction quality.
APPLIED SCIENCES-BASEL
(2023)
Proceedings Paper
Optics
Honghao Zhang, Satoshi Hasegawa, Haruyoshi Toyoda, Yoshio Hayasaki
Summary: The proposed method optimizes holograms in holographic laser processing, significantly increasing the uniformity of optical patterns. This provides high-stability to the holographic laser processing system and makes it suitable for high-precision, high-throughput applications in the field of 3D manufacturing.
OPTICAL TECHNOLOGY AND MEASUREMENT FOR INDUSTRIAL APPLICATIONS CONFERENCE 2021
(2021)
Article
Materials Science, Ceramics
Jin Wang, Yoshio Hayasaki, Fengyun Zhang, Xi Wang, Satoshi Hasegawa, Honghao Zhang, Pingping Wang, Yadi Wang, Shufeng Sun
Summary: A novel three-dimensional holographic femtosecond laser parallel processing method based on the fractional Fourier transform was proposed for arbitrary microstructures inside glass materials. It has shown high speed, high resolution, and excellent control over uniformity and positional accuracy.
CERAMICS INTERNATIONAL
(2022)
Article
Optics
Chengmin Liu, Jun Wang, Yang Wu, Xiangli Lei, Peiding Wang, Han Han, Chun Chen
Summary: A spherical crown diffraction model for curved holographic display is proposed by utilizing occlusion, improving the view angle and optical utilization.
Article
Physics, Multidisciplinary
Gao Qian-Cheng, He Ze-Hao, Liu Ke-Xuan, Han Chao, Cao Liang-Cai
Summary: Currently, spatial light modulators are unable to simultaneously modulate both the amplitude and phase of the wavefront. As a result, when used for holographic display, the complex amplitude of the object wave needs to be encoded into amplitude-only or phase-only computer-generated holograms. The existing optimization algorithms for generating phase-only holograms have issues such as iterative divergence, slow convergence speed, and poor reconstruction quality, which do not meet the requirements for high-quality holographic display. In this study, an accurate adaptive mixed constraint Gerchberg-Saxton algorithm is proposed to address these problems and improve the hologram reconstruction quality.
ACTA PHYSICA SINICA
(2023)
Article
Optics
Yu Zhao, Jing-Wen Bu, Wei Liu, Jia-Hui Ji, Qin-Hui Yang, Shu-Feng Lin
Summary: Currently, a real objects-based full-color holographic system collects data using a DSLR camera array or depth camera, and reconstructs the 3-D scene of the real objects through a spatial light modulator. However, the main challenges faced by high-quality holographic 3-D display are the limited generation speed and low accuracy of computer-generated holograms. This research tackles these issues by developing an RGB-D salient object detection model for more effective and accurate point cloud data, and proposing a divided point cloud gridding method to enhance hologram generation speed.
Article
Chemistry, Physical
Rujia Wang, Yufeng Wang, Yong Yang, Shuowen Zhang, Yunfeng Liu, Jianhua Yao, Wenwu Zhang
Summary: This paper investigates an economical and new processing strategy for ultrashort laser processing, focusing on the laser scribing case. A two-temperature model involving a moving laser source is developed to reveal the temperature evolution under multiple process parameters. The study introduces the energy utilization efficiency and ablation efficiency to analyze the ablation characteristics. A decision-making strategy for balancing quality and productivity is created based on the analysis.
Article
Materials Science, Multidisciplinary
Honghuan Tu, Tingge Yuan, Zhiwei Wei, Yuping Chen, Xianfeng Chen
Summary: The three-dimensional holography technique is widely used in beam shaping, holographic display, and image encryption due to its ability to store depth information and provide more realistic scene reconstruction compared to two-dimensional holography. However, the traditional nanofabrication techniques used for hologram fabrication are complex and time-consuming. In this study, we demonstrate a simpler and more flexible approach to fabricating holograms with depth information inside glass using femtosecond laser direct writing, eliminating the need for complex mask preparation. We then demonstrate and evaluate the reconstruction of three-dimensional objects, discussing experimental optimizations and limitations.
Article
Chemistry, Physical
Christian Lutz, Marcel Jung, Katrin Tschirpke, Cemal Esen, Ralf Hellmann
Summary: In this study, we optimized the spatial drilling sequence and employed multi-spot approaches to reduce the temperature and shorten the processing time in percussion drilling of thin metal sheets.
