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CLEO: QELS - Fundamental science, CLEO_QELS 2015

作者： Calendron, Anne-Laure Çankaya, Hüseyin Cirmi, Giovanni Rossi, Giulio M. Kärtner, Franz X. Center for Free-Electron Laser Science Deutsches Elektronen Synchrotron Department of Physics and University of Hamburg Notkestrasse 85 Hamburg22607 Germany The Hamburg Centre for Ultrafast Imaging Universität Hamburg Luruper Chaussee 149 Hamburg22761 Germany Department of Electrical Engineering Computer Science and Research Laboratory of Electronics Massachusetts Institute of Technology CambridgeMA02139 United States

The phase and stability characterization of white-light supercontinuum generated by sub-picosecond pulses at 1 μm in YAG and sapphire for different pump focusing and duration shows compressible pulses, suitable for a... 详细信息

ISBN: (纸本)9781557529688

关键词： Yttrium aluminum garnet

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Attosecond photonics

Attosecond photonics

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IEEE Photonics Conference (IPC)

作者： Franz X. Kärtner Research Laboratory of Electronics Department of Electrical Engineering and Computer Science Massachusetts Institute of Technology Cambridge MA USA Center for Free-Electron Laser Science DESY University of Hamburg Hamburg Germany

Mode-locked lasers show femtosecond and even attosecond level short term timing jitter. Such ultralow jitter sources enable novel systems. Timing distribution systems for next generation light sources and prototype hi... 详细信息

关键词： Ultrafast optics Photonics Optical pulses Laser mode locking Timing Timing jitter

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A femtosecond-precision, fiber-optic timing transfer system with long-term stable, polarization maintaining output

A femtosecond-precision, fiber-optic timing transfer system ...

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General Assembly and Scientific Symposium, URSI

作者： Jonathan A. Cox Franz X. Kärtner Department of Electrical Engineering and Computer Science and Research Laboratory of Electronics Massachusetts Institute of Technology Cambridge MA USA DESY-Center for Free-Electron Laser Science and Hamburg University Hamburg Germany

A fiber-based, all-optical system for femtosecond-precision, long-term, timing transfer and synchronization of microwave electronics and lasers at the kilometer scale is presented. This approach enables the implementation of femtosecond pulse, X-ray free-electron lasers, owing to the high-precision and robust operation. The system incorporates a fiber polarization controller for long-term synchronization of remote lasers, and operates with an optical timing detector based on balanced optical cross-correlation. We demonstrate continuous, unaided timing distribution over 168-hours with 5 fs rms precision. Also, the first demonstration of timing transfer from local to remote ultrafast, fiber laser with an all-optical, ultrafast technique is shown for over 5 hours with 4 fs rms transfer precision. This represents timing transfer over 340 m of fiber with an unprecedented fractional relative timing stability of 10 -19 . A study of linear and non-linear effects impacting performance is presented, along with design guidelines, while it is shown that minimization of polarization mode dispersion and non-linearity are critical design considerations for optimal performance.

关键词： Timing Optical fiber dispersion Optical fiber polarization Optical fiber devices Ultrafast optics Masers

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Intelligent Food Identification System Using Improved YOLOv8

Intelligent Food Identification System Using Improved YOLOv8

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2024 International Symposium on computer science and Educational technology (ISCSET)

作者： Francia Nitiavintokana Md Abdur Rouf Xiaoyu Yu Haibin Wu Aili Wang Yuji Iwahori Heilongjiang Province Key Laboratory of Laser Spectroscopy Technology and Application Harbin University of Science and Technology Harbin China College of Electron and Information University of Electronic Science and Technology of China Zhongshan Institute Zhongshan China Department of Computer Science Chubu University Aichi Japan

ISBN: (数字)9798350390803

ISBN: (纸本)9798350390810

The field of computer vision has witnessed significant advances in object detection with real-world applications ranging from autonomous driving to surveillance systems. Due to its importance in a number of areas, such as dietary evaluation, food industry automation, and health monitoring, food identification has attracted a lot of interest in this context. The suggested approach makes use of the capabilities of two cutting-edge object recognition models, YOLOv8. Because of its speed and accuracy, YOLOv8 is a great option for real-time food detection in a variety of settings. Our most recent YOLOv8 model is called BiTrains-YOLOv8. Supervision techniques are applied to improve the combined model's performance even more. This increases overall detection accuracy and helps the algorithm to more effectively generalize to novel food items. Based on the detection results, 96.7% of an average of detection accuracy, 96.4% for precision, 95.7 % for recall, and 96.04 % for F1-Score were obtained. The results show that the combination of YOLOv8 and BiTrains-YOLOv8 improved model techniques, significantly improved the performance of food detection, outperforming the previous methods in terms of accuracy, speed and robustness. Furthermore, the paper analyzes potential real-world applications of the system, such as calorie counting, dietary assessment and smart kitchen automation. Implications of advanced intelligent food detection in healthcare, the culinary industry and personalized nutrition are also discussed. In conclusion, the results provide valuable insights for pushing the boundaries of food recognition technology, with promising applications in various fields that promote healthy lifestyles and improve efficiency in food-related processes.

关键词： Training Industries Accuracy Automation Surveillance Object detection Medical services Robustness Real-time systems Object recognition

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Coherent synthesis of ultra-broadband optical parametric amplifiers

Coherent synthesis of ultra-broadband optical parametric amp...

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High Intensity Lasers and High Field Phenomena, HILAS 2011

作者： Manzoni, C. Huang, S.W. Cirmi, G. Moses, J. Kärtner, F.X. Cerullo, G. IFN-CNR Dipartimento di Fisica Politecnico di Milano Piazza L. Da Vinci 32 20133 Milano Italy Department of Electrical Engineering and Computer Science and Research Laboratory of Electronics Massachusetts Institute of Technology Cambridge MA 02139 United States Center for Free-Electron Laser Science DESY and University of Hamburg Notkestraße 85 D-22607Hamburg Germany

We report on coherent synthesis of two ultra-broadband optical parametric amplifiers, resulting in octave-spanning (500-1000 nm) spectra supporting nearly single-cycle sub-4-fs pulse duration. Synthesized pulse timing... 详细信息

ISBN: (纸本)9781557529046

关键词： Optical parametric amplifiers

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High-order harmonic generation in Xe, Kr, and Ar driven by a 2.1-μm source: High-order harmonic spectroscopy under macroscopic effects

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Physical Review A 2012年第4期86卷 043412-043412页

作者： Kyung-Han Hong Chien-Jen Lai Vasileios-Marios Gkortsas Shu-Wei Huang Jeffrey Moses Eduardo Granados Siddharth Bhardwaj Franz X. Kärtner Department of Electrical Engineering and Computer Science and Research Laboratory of Electronics Massachusetts Institute of Technology (MIT) Cambridge Massachusetts 02139 USA IKERBASQUE Basque Foundation for Science Spain Center for Free-Electron Laser Science DESY and Department of Physics Hamburg University Notkestraße 85 D-22607 Hamburg Germany

We experimentally and numerically study the atomic response and pulse propagation effects of high-order harmonics generated in Xe, Kr, and Ar driven by a 2.1-μm infrared femtosecond light source. The light source is an optical parametric chirped-pulse amplifier, and a modified strong-field approximation and three-dimensional pulse propagation code are used for the numerical simulations. The extended cutoff in the long-wavelength-driven high-order harmonic generation has revealed the spectral shaping of high-order harmonics due to the atomic structure (or photorecombination cross section) and the macroscopic effects, which are the main factors of determining the conversion efficiency besides the driving wavelength. Using precise numerical simulations to determine the macroscopic electron wave packet, we are able to extract the photorecombination cross sections from experimental high-order harmonic spectra in the presence of macroscopic effects. We have experimentally observed that the macroscopic effects shift the observed Cooper minimum of Kr from 80 eV to 60–70 eV and wash out the Cooper minimum of Ar. Measured high-harmonic conversion efficiencies per harmonic near the cutoff are ∼10−9 for all three gases.

关键词： HIGH-order derivatives (Mathematics) HARMONIC analysis (Mathematics) PHYSICS experiments FEMTOSECOND lasers CROSS-sectional method ATOMIC structure

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Coherent synthesis of ultra-broadband optical parametric amplifiers

Coherent synthesis of ultra-broadband optical parametric amp...

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High Intensity Lasers and High Field Phenomena, HILAS 2012

ISBN: (纸本)9781557529398

关键词： Optical parametric amplifiers

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Cascaded optical parametric chirped-pulse amplification for multi-cycle THz-wave generation

Cascaded optical parametric chirped-pulse amplification for ...

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International Conference on Ultrafast Phenomena, UP 2016

作者： Hemmer, M. Reichert, F. Cirmi, G. Ravi, K. Ahr, F. Lemery, F. Calendron, A.-L. çankaya, H. Schimpf, D.N. Zapata, L.E. Mücke, O.D. Matlis, N.H. Kärtner, F.X. Center for Free-Electron Laser Science Deutsches Elektronen Synchrotron Notkestrasse 85 Hamburg22607 Germany Department of Physics University of Hamburg Hamburg22761 Germany The Hamburg Centre for Ultrafast Imaging Universität Hamburg Luruper Chaussee 149 Hamburg22761 Germany Department of Electrical Engineering and Computer Science and Research Laboratory of Electronics Massachusetts Institute of Technology CambridgeMA02139 United States

We experimentally demonstrate cascaded optical parametric chirped-pulse amplification, an efficient method for the amplification of multi-cycle THz-frequency waves. Experimental results are supported by numerical simu... 详细信息

ISBN: (纸本)9781943580187

关键词： Amplification

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Yb-fiber oscillator based, few-cycle ultrafast source at 850nm

Yb-fiber oscillator based, few-cycle ultrafast source at 850...

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Pacific Rim Conference on Lasers and Electro-Optics (CLEO/Pacific Rim)

作者： Hung-Wen Chen Haider Zia JinKang Lim Guoqing Chang Franz X. Kärtner Department of Electrical Engineering and Computer Science and Research Laboratory of Electronics Massachusetts Institute of Technology Cambridge MA USA Center for Free-Electron Laser Science DESY and Department of Physics University of Hamburg Hamburg Germany Massachusetts Institute of Technology Cambridge MA US

We demonstrate an Yb-fiber oscillator based, broadband (~170 nm) laser source centered at 850 nm. The spectrum generated by fiber-optic Cherenkov radiation produces ~11-fs compressed pulses after phase compensation us... 详细信息

ISBN: (纸本)9781467364751

关键词： Free electron lasers Laser mode locking Fiber lasers Laser theory Oscillators Optical fiber dispersion Optical pulses

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Coherent synthesis of ultra-broadband optical parametric amplifiers

Coherent synthesis of ultra-broadband optical parametric amp...

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Advanced Solid-State Photonics, ASSP 2012

作者： Manzonil, C. Huang, S.W. Cirmi, G. Moses, J. Kärtner, F.X. Cerullo, G. IFN-CNR Dipartimento di Fisica Politecnico di Milano Piazza L. Da Vinci 32 20133 Milano Italy Department of Electrical Engineering and Computer Science Research Laboratory of Electronics Massachusetts Institute of Technology Cambridge MA 02139 United States Center for Free-Electron Laser Science DESY and University of Hamburg Notkestraße 85 D-22607Hamburg Germany

关键词： Optical parametric amplifiers

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