Shanghai Institute of Optics and Fine Mechanics,Chinese Academy of Sciences
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A High-Energy, 100 Hz, Picosecond Laser for OPCPA Pumping
No full textNational Science Foundation of China (NSFC) [11127901, 11134010]; Shanghai Sailing Program [15YF1413500]; Strategic Priority Research Program of the Chinese Academy of Sciences [XDB1603]; International S&T Cooperation Program of China [2016YFE0119300]A high-energy diode-pumped picosecond laser system centered at 1064 nm for optical parametric chirped pulse amplifier (OPCPA) pumping was demonstrated. The laser system was based on a master oscillator power amplifier configuration, which contained an Nd: YVO4 mode-locked seed laser, an LD-pumped Nd: YAG regenerative amplifier, and two double-pass amplifiers. A reflecting volume Bragg grating with a 0.1 nm reflective bandwidth was used in the regenerative amplifier for spectrum narrowing and pulse broadening to suit the pulse duration of the optical parametric amplifier (OPA) process. Laser pulses with an energy of 316.5 mJ and a pulse duration of 50 ps were obtained at a 100 Hz repetition rate. A top-hat beam distribution and a 0.53% energy stability (RMS) were achieved in this system
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
Broadband optical parametric chirped pulse amplification in K3B6O10Br crystal near 800 nm
No full textNational Natural Science Funding of China [NSFC 61378030, NSFC 61521093, NSFC 51425206]Broadband optical parametric chirped pulse amplification (OPCPA) of the K3B6O10Br (KBOB) crystal at a central wavelength of 800 nm has been demonstrated for the first time. Using type-1 non-collinear phase matching, a 52 nm FWHM bandwidth was achieved around 800 nm. The 0.25 mJ signal was amplified to 23.92 mJ at the pump intensity of 2.1 GW cm(-2). The energy gain was 95.68. After compression, 15.31 mJ to 31.9 fs pulses were obtained. The results confirm that KBOB crystal is a potential alternative for efficient, broadband OPCPA near 800 nm
Effects of SiO2 on properties and structures of neodymium doped P2O5-Al2O3-Li2O-MgO-Sb2O3 glasses
No full textMINECO of Spain [MAT2013-48246-C2-1-P]; CSIC [I-link+0959]; [J-GFZX0205010501.7]Effects of substitutions of SiO2 for Al2O3 and P2O5 in a single base phosphate glass, Nd3+: P2O5-Al2O3-Li2O-MgO-Sb2O3, on glass structure and properties are investigated. For glasses with Al2O3 replaced by SiO2, coordination number of Al becomes larger, and P=O bond and Si with six oxygens coordinated emerge. For glasses with P2O5 replaced, coordination number of Al becomes smaller, P(Q(2)) changes to P(Q(1)) and all Si units are four coordinated. The reason for coordination number of Al and Si change may come from the variation of terminal oxygen quantity. The relationship between glass structure and physical (rho, T-g, CTE), mechanical (E), and optical properties (n(D), sigma(em), Delta lambda(em)) are builded
Polarized spectral properties of Sm:CaGdAlO4 crystal for reddish-orange laser
No full textChina Postdoctoral Science Foundation [2016M592466]; National Natural Science Foundation of China [61621001]; National Key Research and Development Program of China [2016YFB0701002]The crystal growth, polarized spectral properties, Judd-Ofelt (JO) analysis and lifetime of Sm:CaGdAlO4 (Sm:CGA) crystal were reported for the first time. Sm:CGA crystal with size of 44 x 33 mm(3) was grown by the floating zone (FZ) method. The peak absorption cross-sections at 407 nm were calculated to be 3.41 x 10(-20)cm(2) and 3.20 x 10(-20)cm(2) for the a and x polarization, and the largest stimulated emission cross-sections at 601 nm were 5.10 x 10(-21)cm(2) and 4.66 x 10(-21)cm(2), respectively. The absorption and emission cross-sections were several times larger than that of Sm:LiYF4. The JO intensity parameters of Omega(2), Omega(4) and Omega(6) were calculated to be 3.0 x 10(-20)cm(2), 6.1 x 10-20cm(2) and 6.5 x 10(-20)cm(2), respectively. The lifetime of the (4)G(5/2) level was obtained to be 0.69 ms. All the results indicate that Sm:CGA crystal is a potential laser host for the reddish-orange laser operation
Preparation, upconversion luminescence, and solid-state NMR studies of water-soluble hexagonal NaScF4:Yb/Er microcrystals
No full textNational Natural Science Foundation of China [NSFC 61475174, NSFC 61675218]; Chinese Academy of SciencesWater-soluble hexagonal NaScF4:Yb/Er upconversion microcrystals (UCMCs) were synthesized using the hydrothermal method. The upconversion photoluminescence properties of NaScF4:xYb/2%Er microcrystals (x=4-20%) were characterized under a 980-nm-wavelength laser excitation. The dependence of red/green (R/G) ratio on the concentration of Yb3+ ions was investigated. The local environments of dopant ions (Yb3+, Er3+) in NaScF4 were studied using multiple solid-state nuclear magnetic resonance (NMR) techniques. The F-19 single pulse and F-19{Na-23} and F-19{Sc-45} rotational echo double resonance (REDOR) techniques proved that the dopant rare-earth ions (Yb3+, Er3+) preferred to substitute Na+ rather than Sc3+ ions. Such solid-state NMR techniques provide a novel approach to study new phosphors. (C) 2017 Elsevier B.V. All rights reserved
Structural Studies of Bi2O3-NaPO3 Glasses by Solid State Nuclear Magnetic Resonance and X-ray Photoelectron Spectroscopy
No full textNational Natural Science Foundation of China [NSFC 61475174, NSFC 61675218]; 100 Talents Program of the Chinese Academy of SciencesGlasses in the system xBi(2)O(3)-(100 - x)NaPO3 were prepared using transitional melting quenching and characterized using solid state nuclear magnetic resonance (SSNMR), X-ray photoelectron spectroscopy (XPS), and Fourier-transform infrared spectroscopy (FT-IR). The addition of Bi2O3 results in the depolymerization of the phosphorus chain and the formation of Q((n)) (n = 0, 1, 2) phosphorus species, where n represents the number of P-Q-P bonds that can be quantified using P-31 magic angle spinning (MAS) NMR and constant-time double-quantum based,dipolar recoupling effects nuclear alignment reduction (CT-DQDRENAR). The Na-23{P-31}, P-31{Na-23}, and XPS results, consistently prove that both Na+ and Bi3+ ions are bounded by phosphorus tetrahedron [PO4](3-). Unlike other trivalent ions such as Ga3+ and Al3+, which connect with the phosphorus tetrahedron by corner-sharing, Bi3+ ions were first proved to share edge with the phosphorus tetrahedron by the analysis of P-31 spectra, taking the charge balance,and bond valence consideration into account. Such a difference in connectivity result in significant structural differences
The Cr-doping effect on white light emitting properties of Ce:YAG phosphor ceramics
No full textNational Natural Science Foundation of China [61475172]The Cr/Ce-doped YAG transparent ceramic was fabricated by the solid-state reaction in vacuum. The Cr/Ce-doped YAG ceramic phosphor effectively complement the red spectral component and improve the color rendering performance when excited by blue light that is due to the effective energy transfer between Cr3+ ion and Ce3+ ion. However, the energy transfer from Ce3+ to Cr3+ ion leads to energy loss and therefore the luminous efficacy of the WLED which is composed of blue LED chip and the Cr/Ce-doped YAG ceramic phosphor decreases. The composite phase structure of ceramic phosphor is designed for improving the extraction efficacy and increasing the luminous efficacy by breaking the total internal reflection (TIR) at the interface between air and ceramic
Laser radar: historical prospective-from the East to the West
No full textThis article discusses the history of laser radar development in America, Europe, and Asia. Direct detection laser radar is discussed for range finding, designation, and topographic mapping of Earth and of extraterrestrial objects. Coherent laser radar is discussed for environmental applications, such as wind sensing and for synthetic aperture laser radar development. Gated imaging is discussed through scattering layers for military, medical, and security applications. Laser microradars have found applications in intravascular studies and in ophthalmology for vision correction. Ghost laser radar has emerged as a new technology in theoretical and simulation applications. Laser radar is now emerging as an important technology for applications such as self-driving cars and unmanned aerial vehicles. It is also used by police to measure speed, and in gaming, such as the Microsoft Kinect. (C) The Authors. Published by SPI
Programmable uniformity correction by using plug-in finger arrays in advanced lithography system
No full textInternational Science & Technology Cooperation Programs of China [2011DER10010, 2012DFG51590]; Science and Technology Commission of Shanghai Municipality [14YF1406300]; National Science and Technology Major Project of China [2011ZX02402]Illumination integrated non-uniformity (IINU) is one of the key factors to determine the resolution and Critical Dimension Uniformity (CDU) which are important performance parameters in advanced lithography system. To further reduce the IINU, uniformity correction technology has been adopted. In this paper, an approach of programmable uniformity correction with higher flexibility and better correction capability is proposed. The method is composed of variable attenuation correction element arrays which are inserted into the edge of an illumination field to shield the energy through programming. Based on the proposed method, a programmable uniformity correction unit is applied to an illumination optical system. The simulation results show that the value of the corrected IINU reaches less than 0.25%, which satisfies the requirements of IINU hi advanced lithography system, and the energy loss is less than 1.1%. It verifies the higher flexibility and better correction capability of the proposed method