149,187 research outputs found
Advances in Ultrafast Optics Advances in optical physics ;, v. 6./ Fei He and 5 others ; edited by Zhiyi, Wei.
No full textIn English.Includes bibliographical references and index.Wei, Zhiyi / Fang, Shaobo -- Zeng, Heping -- He, Fei / Liao, Yang / Lin, Jintian / Ni, Jielei / Zeng, Bin / Qiao, LingLing / Cheng, Ya -- Li, Derong / Lv, Xiaohua / Luo, Qingming / Zeng, Shaoqun -- Quan, Wei / Lai, Xuanyang / Liu, Xiaojun / Chen, Jing -- Wang, Shufeng / Meng, Kang / Gong, Qihuang -- Frontmatter -- Preface -- Contents -- 1. Ultrafast ultrahigh-intensity laser pulses / 2. Femtosecond optical frequency combs / 3. Three-dimensional integration of hybrid functionalities in transparent dielectrics by femtosecond laser direct writing / 4. Spatial and temporal broadening of a femtosecond laser pulse after angular dispersion / 5. Atomic physics in ultrafast intense laser fields / 6. Ultrafast spectroscopic techniques and ultrafast photophysics in polymers / Index.1 online resource (443 pages)
The development of high power fibre chirped pulse amplification systems
No full textWith its broad gain bandwidth and high optical conversion efficiency, ytterbium (Yb)-doped silica fiber represents an attractive medium for the generation and amplification of ultrashort optical pulses. Research interest in Yb-doped fiber chirped pulse amplifier (CPA) systems first appeared in the late 1990s. However, the potential advantages and capabilities of Yb-doped fiber CPA systems were not fully studied during the early research. Further scaling of both the average power and the pulse energy have now become possible with the development of several key technologies that are associated with Yb-doped fiber CPA systems. Finally, the development of a novel fiber CPA system operating with strong selfphase-modulation (SPM) is described, which applied adaptive shaping of the spectral phase of the input pulses. The pre-compensation of both SPM induced phase distortion at high energies, and residual dispersion from mismatched stretcher/compressor technologies at low energies are investigated
Dataset for "Coherent illumination spectroscopy of nanostructures and thin films on thick substrates"
No full textData for the paper He, F., MacDonald, K., & Fang, X. (2018). Coherent illumination spectroscopy of nanostructures and thin films on thick substrates. Optics Express.
The paper has 5 figures in total, from Figure 1 to Figure 5.Only Figures 2(b), 3(b), 4(a), 4(b) and 5 have data. The data in each of these figures are recorded in a separate sheet in this dataset file.</span
Coherent control of wavefronts by planar photonic metasurfaces
No full textThe optical properties of materials can manifest differently in traveling and standing light waves. In standing waves, “coherent control” of the energy exchange between incident and scattered waves enables control of light with light without nonlinearity, at arbitrarily low intensity and on ultrashort (few optical cycle) timescales. This thesis reports on my research efforts towards application of coherent control techniques for shaping the wavefronts of light scattered by planar photonic metasurfaces: I show for the first time that the coherent control paradigm can be applied to optically thick and/or asymmetric sample/device structures, where previously only vanishingly thin (subwavelength thickness) structures were considered. I have derived the requisite illumination conditions for electric and magnetic field standing wave excitation of substrate-supported (e.g. at an air-glass substrate) meta surface structures; and numerically demonstrated applications to selective excitation spectroscopy and for thin film characterisation. I have introduced a new mechanism for active tuning of gradient index meta surfaces via coherent control of the phase gradient itself – turning what is conventionally a constant in the Generallized Snell’s law into a variable. This is demonstrated in the development of a meta surface design providing, through coherent selective excitation of Mie-type resonances in Si nano-pillars, coherently controlled beam steering (with no moving parts) over a continuous 9.1° range. I have also discussed its potential use for solid state Lidar
Fei-yen wai-zhuan the true era of its birth and investigation of its author
No full textFei-yen wai-zhuan 飛燕外傳 (The Unofficial Biography of [Zhao] Fei-yen) is one of the classical-language fictions in traditional China, describing the famous romance between Emperor Cheng-di 成帝 and Zhao Fei-yen 趙飛燕 sisters in the Former Han Dynasty. The author is attributed with Ling Xüan 伶玄, who definitely had confessed that he was living with the Former Han Dynasty in his brief autobiography. However, it was too suspicious to believe, from the beginning of its appearance in the Southern Song Dynasty, scholars have been puzzled to determine the true era of its birth. Through their discussions, now it is widely accepted that Fei-yen wai-zhuan was born during the Six Dynasties, not in the Tang Dynasty, though it is still lacking in conclusive evidence. But some insist that it could be compared with the great masterpieces of Tang-tales, like Ying-ying zhuan 鶯鶯傳, Li Wa zhuan 李娃傳, Huo Xiao-yü zhuan 霍小玉傳, which belonged to the Tang Dynasty. Then should we say that Fei-yen wai-zhuan was a premature masterpiece? It still remains a great mystery to all, including its author Ling Xüan himself. This study, paying attention to the text itself, proves this tale should belong to the Tang Dynasty. Its main keywords are two, Zhen-la 眞臘 and Qi-chu Ling-hua jing 七出菱花鏡 (Water-chestnut flower shaped bronze mirror, circled by seven petals). The former, used first in the historical records in China was in the Sui Dynasty Da-ye 大業 12years(616), and the latter one likely appeared after reign of Empress Wu(690--705). These facts simply tell us Fei-yen wai-zhuan was born in the Tang Dynasty. The true author of this tale is Niu Seng-ru 牛僧孺, a famous prime minister of late Tang and was also a well-known writer of Tang-tales, who authored Xüan-guai lu 玄怪錄. We could know the close affinities between Fei-yen wai-zhuan and Xüan-guai lu. As a drafted scholar-official, all of Niu's life had been under the strife in bureaucracy with the factional parties at that time. Once the opposition party blamed Niu for violating his majesty, to write the tale Zhou Qin xing-ji 周秦行記 named Niu Seng-ru. Though its writer was anonymous, Niu was nearly accused of injury to the majesy (Lèse majesté). I contend Niu decided to write Fei-yen wai-zhuan under a pseudonym to make counterattack against a recreant writer in the same manner and to regain true pride for himself
Coherent illumination spectroscopy of nanostructures and thin films on thick substrates
No full textMany nanophotonic and nanoelectronic devices contain nanostructures and ultrathin films on the surface of a thick, effectively semi-infinite, substrate. Here we propose a spectroscopic technique based upon coherent illumination, for characterising such samples. The method uses two counter-propagating light beams to generate specific field configurations at the substrate surface plane, which can be modulated, for example, to selectively excite and thereby discriminate between resonant modes of plasmonic nanostructures, or to measure thin films thickness with nanometre resolution. The technique offers a variety of practical applications for the coherent illumination in solid state physics, analytical chemistry, biochemistry and nano-engineering
Continuous beam steering via controlling light with light on a dielectric metasurface
No full textIn this oral presentation, we demonstrate using two coherent light beams to dynamically control the output angle of light from a silicon metasurface. Continuous tuning of ~10 degrees is observed, suggesting potential applications in Lidar and facial recognition
Beam steering and dynamic focusing by coherent control of light with light on metasurfaces
No full textWe report continuous ‘coherently controlled’ tuning of the wavefront of light scattered by phase-gradient silicon metasurfaces, which enables optical-frequency beam steering and dynamic focusing without moving parts
Continuous beam steering by coherent light-by-light control of dielectric metasurface phase gradient
No full textContinuous and reversible tuning of the properties of optical metasurfaces, as a functionality that would enable a range of device applications, has been a focus of the metasurface research field in recent years. Tuning mechanisms proposed and demonstrated so far have generally relied upon changing the morphology of a metasurface or the intrinsic properties of its constituent materials. Here we introduce, via numerical simulation, an alternative approach to achieve continuous tuning of gradient metasurface response, and illustrate its potential application to the challenge of continuous beam steering, as required for example in LIDAR and machine vision systems. It is based upon the coherent illumination of a silicon nano-pillar metasurface with two counter-propagating beams. Control of the input beams’ relative phase and intensity enables tuning of the individual nano-pillars’ electromagnetic response and thereby the phase gradient of the array, which in turn steers the direction of the output beam continuously over an angular range of approximately 9 degrees
Coherent absorption at interfaces for film thickness measurement and plasmonic selective excitation
No full textIn this oral presentation, we demonstrate using two coherent light beams to measure the thickness of absorptive thin films and selectively excite plasmonic resonances at the surface of transparent bulk substrates
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