Shanghai Institute of Optics and Fine Mechanics,Chinese Academy of Sciences
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Influence of SiO2 on the Stark splitting and spectroscopic properties of Yb3+ in phosphate glass
No full textNational Natural Science Foundation of China [61177083]This study focuses on the Stark splitting, spectroscopic properties and lasing performance parameters of Yb3+ in conventional phosphate glass modified by SiO2. Introducing silica into phosphate glass is an effective method to increase the maximum Stark splitting energy of F-2(7/2) (E-d). The E-d in phosphate glass with 25 mol% silica was enhanced by 203 cm(-1). Interestingly, phosphate glass with 5 mol% silica offers small coefficients of thermal expansion, most obvious Stark splitting improvement, higher stimulated emission cross-section, longer lifetime and the largest SFL, which may ascribed to the formation of Si-(6). From the point of the comprehensive performance of the material, it suggests that the introduction of small amount of SiO2 is better for Yb3+ doped phosphate glass. (C) 2017 Published by Elsevier B.V
Temporal speckle method for measuring three-dimensional surface of large-sized rough glass
No full textTo provide accurate three-dimensional (3-D) data for production and processing, 3-D surface measurement is always an essential step to the production of glass. Profilometry and Interferometry are traditional measurement apparatus, referring to different procedures. Although more precise, Interferometry cannot be used in milling procedure, owing to the scattering property of rough glass. While as a widely used Profilometry, Coordinate Measuring Machine (CMM) employs a probe for measuring by contacting surface directly. It should be noted that such a time-consuming machine is not practical for measuring large-sized rough glass, so a novel designed method called temporal speckle is introduced to a non-contact binocular 3-D measurement system for measuring. Specifically, N band-limited binary patterns are sequentially projected to rough glass from a pattern generation device, such patterns have been proved to depress scattering properties of rough surface. The whole binocular 3-D measurement system can finish a single measurement in one second with a standard deviation less than 73.44um. This system performs fast and accurate 3-D surface measurement for large-sized rough glass block
Tailoring femtosecond 1.5-mu m Bessel beams for manufacturing high-aspect-ratio through-silicon vias
No full textNational Natural Science Foundation of China [61327902, 11134010]; National Basic Research Program of China [2014CB921300]Three-dimensional integrated circuits (3D ICs) are an attractive replacement for conventional 2D ICs as high-performance, low-power-consumption, and small-footprint microelectronic devices. However, one of the major remaining challenges is the manufacture of high-aspect-ratio through-silicon vias (TSVs), which is a crucial technology for the assembly of 3D Si ICs. Here, we present the fabrication of high-quality TSVs using a femtosecond (fs) 1.5-mu m Bessel beam. To eliminate the severe ablation caused by the sidelobes of a conventional Bessel beam, a fs Bessel beam is tailored using a specially designed binary phase plate. We demonstrate that the tailored fs Bessel beam can be used to fabricate a 2D array of approximately circle divide 10-mu m TSVs on a 100-mu m-thick Si substrate without any sidelobe damage, suggesting potential application in the 3D assembly of 3D Si ICs
Accelerating gradient improvement from hole-boring to light-sail stage using shape-tailored laser front
No full textNational Natural Science Foundation of China [11125526, 11335013, 11575274, 11305236]; Shanghai Natural Science Foundation [13ZR1463300]The accelerating gradient of a proton beam is a crucial factor for the stable radiation pressure acceleration, because quickly accelerating protons into the relativistic region may reduce the multidimensional instability grow to a certain extent. In this letter, a shape-tailored laser is designed to accelerate the protons in a controllable high accelerating gradient in theory. Finally, a proton beam in the gigaelectronvolt range with an energy spread of similar to 2.4% is obtained in one-dimensional particle-in-cell simulations. With the future development of the high-intense laser, the ability to accelerate a high energy proton beam using a shape-tailored laser will be important for realistic proton applications, such as fast ignition for inertial confinement fusion, medical therapy, and proton imaging. Published by AIP Publishing
An end pumped all internal reflection small-sized slab picosecond laser amplifier
No full textNational Science Foundation of China (NSFC) [11127901, 11134010]; Shanghai Sailing Program [15YF1413500]An end pumped all internal reflection small-sized slab picosecond laser system amplifier is proposed and demonstrated based on the common Nd:YAG crystal. A cylinder lens is introduced to pre-compensate for the one-dimensional thermal effect caused by the high power pumping laser. The maximum output powers of 6.6 and 6.3 W are obtained at the absorbed pumping power of 25 W without and with a cylinder mirror, and the corresponding optical conversion efficiencies are about 10.4% and 9.3% respectively. The measured M-2 factors along the slow and fast axes are 1.71 and 2.47 respectively. The instability of the maximum output laser is below 0.8% (RMS) within measuring time up to 15 min. It is demonstrated that the all internal reflection slab can support long enough optical gain distance to realize the signal laser amplification for the newly developed crystal even with small size and low doped concentration
Comparison of high-energy multi-pass Ti:sapphire amplifiers with a different Ti-dopant concentration
No full textWe experimentally compare the output abilities of lightly and heavily doped Ti:Sapphire (Ti:S) amplifiers with diameters as large as 150 mm. Although a lightly doped Ti: S is more favorable to overcome parasitic lasing (PL) and transverse amplified spontaneous emission (TASE), the self-phase-modulation (SPM) effect becomes more pronounced when a longer crystal is used. Recompression of the amplified, stretched pulses can be seriously affected by the SPM effect. We then propose a temporal multi-pulse pump scheme to suppress PL and TASE in a thin, heavily doped Ti: S crystal. This novel temporal multi-pulse pump technique can find potential applications in 10 PW chirped-pulse amplification laser systems
Design and simulation of a single-cycle source tunable from 2 to 10 micrometers
No full text100 Talents Program of CAS; National Natural Science Foundation of China [61475169, 61521093, 11127901]; Youth Innovation Promotion Association of CAS; Strategic Priority Research Program of the Chinese Academy of Sciences [XDB16]; International S&T Cooperation Program of China [2016YFE0119300]We present the design of a novel single-cycle infrared source tunable from 2 to 10 lam. We simulate the optical parametric amplification (OPA) in BBO and the difference frequency generation (DFG) in AGS based on coupled second-order three-wave nonlinear propagation equations. We combine this with the unidirectional pulse propagation equation, which models the generation of the initial supercontinuum seed in sapphire and the final self compression in YAG, ZnS, and GaAs, respectively. The obtained results indicate that single cycle pulses can be produced in a tunable range of 2 to 10 lam. (C) 2017 Optical Society of Americ
Dynamics of electron injection in a laser-wakefield accelerator
No full textDFG [Transregio TR18]; Euratom research and training program of the EUROfusion Consortium [633053]; Munich Centre for Advanced Photonics (MAP); Swedish Research Council [2016-05409]; Max Planck Society (MPS)-Chinese Academy of Sciences (CAS) Joint Doctoral Promotion Program; National Natural Science Foundation of China [11505264]The detailed temporal evolution of the laser-wakefield acceleration process with controlled injection, producing reproducible high-quality electron bunches, has been investigated. The localized injection of electrons into the wakefield has been realized in a simple way-called shock-front injection-utilizing a sharp drop in plasma density. Both experimental and numerical results reveal the electron injection and acceleration process as well as the electron bunch's temporal properties. The possibility to visualize the plasma wave gives invaluable spatially resolved information about the local background electron density, which in turn allows for an efficient suppression of electron self-injection before the controlled process of injection at the sharp density jump. Upper limits for the electron bunch duration of 6.6 fs FWHM, or 2.8 fs (r. m. s.) were found. These results indicate that shock-front injection not only provides stable and tunable, but also few-femtosecond short electron pulses for applications such as ultrashort radiation sources, time-resolved electron diffraction or for the seeding of further acceleration stages. Published by AIP Publishing
Isolated attosecond pulse generation with few-cycle two-color counter-rotating circularly polarized laser pulses
No full textNational Natural Science Foundation of China [61690223, 11561121002, 61521093, 11227902, 11404356, 11574332]; Strategic Priority Research Program of the Chinese Academy of Sciences [XDB16]Most of the schemes for generating isolated attosecond pulses (IAP) are sensitive to the carrier-envelope phase (CEP) of the driving lasers. We propose a scheme for generating IAP using two-color counter-rotating circularly polarized (TCCRCP) laser pulses. The results demonstrate that the dependence of the IAP generation on CEP stability is largely reduced in this scheme. IAP can be generated at most of CEPs. Therefore, the experiment requirements become lower
Laser performance of a broadband wavelength tunable Yb:germanophosphate glass with direct diode pumping
No full textNational Science Foundation of China (NSFC) [11504394, 61521093, 61378030]The laser performance of a new Yb:germanophosphate (Yb:GP) glass is investigated. A maximum output power of 826 mW at 1063 nm is achieved with direct diode pumping at 976 nm. The wavelength is tuned from 1034.47 to 1070.83 nm, corresponding to a tuning range of 36.36 nm. Thermal lens effects are investigated to optimize the optical cavity