Shanghai Institute of Optics and Fine Mechanics,Chinese Academy of Sciences
Not a member yet
13355 research outputs found
Sort by
Dispersion management of the SULF front end
No full textNational Basic Research Programme of China [011CB808101]; Strategic Priority Research Programme of the Chinese Academy of Sciences [XDB16]; National Natural Science Foundation of China [61521093, 61078037, 11127901, 11134010, 61205208, 11204328]To manage dispersion of the front end in the Shanghai Superintense Ultrafast Laser Facility (SULF), which is a largescale project aimed at delivering 10 PW laser pulses, a stretcher based on a combination of a grating and a prism (grism) pair is inserted between an Offner-triplet-type stretcher and a regenerative amplifier to reduce high-order dispersion introduced by optical materials at the amplification stage. The alignment of the grism pair is implemented by controlling the far-field pattern of the output beam of the grism pair. The energy of the front end reaches up to 7 J at a 1-Hz repetition rate. Experimental results show that the pulse duration can be compressed to 22.4 fs and the spectral distortion over the spectrum is less than 2.25 rad
Electron localization of H-3(+) and HeH2+ in an ultrashort ultraviolet laser field
No full textNational Natural Science Foundation of China [11127901, 61521093, 11134010, 11227902, 11222439, 11274325]; National 973 Project [2011CB808103]Electron localization in the dissociation of the molecular ions H-3(+) and HeH2+ in an intense ultrashort ultraviolet laser pulse is studied with the Schrdinger equation. Two different dissociation channels, H-3(+) + n gamma -> H-2 + p and H-3(+) + n gamma -> H-2(+) + H, and HeH2++ n gamma -> He+ + p and HeH2++ n gamma -> alpha + H, for H-3(+) and HeH2+, are investigated, respectively. The numerical and analytical results both show that, for a molecular ion with an asymmetric double-well Coulomb potential, most electrons of the 1s sigma(g) state are localized at the potential well with lower energies. For electrons of the 2p sigma u state, most are localized at the potential well with higher energies when in a single ultraviolet laser pulse. Therefore, for H-3(+), most electrons of the dissociation state are stabilized at the potential well with higher energies (H+), for the lowest dissociation state is the 2p sigma(u) state. Most of the electrons of the dissociation state of HeH2+ are captured by the potential well with lower energies (He2+), because the lowest dissociation state is the 1ssg state and the 2p sigma(u) state is bounded
Energetic radially polarized few-cycle pulse compression in gas-filled hollow-core fiber
No full textNational Natural Science Foundation of China (NSFC) [61205208]; Strategic Priority Research Program of the Chinese Academy of Sciences [XDB1603]; International S&T Cooperation Program of China [2016YFE0119300]The compression of high-energy, radially polarized pulses in a gas-filled hollow-core fiber (HCF) is theoretically studied. The simulation results indicate that a 40-fs input pulse can be compressed to a full-width at half-maximum of less than 9 fs when the pulse energy reaches 7.0 mJ with a transmission efficiency of more than 67% after propagating through a 1-m-long, 500-mu m diameter HCF filled with neon. Furthermore, the spatio-temporal intensity distributions of the compressed pulses with different initial input energies are studied, and the numerical results indicate that the spatio-temporal intensity distributions are more uniform for lower input pulse energies
Extreme case of Faraday effect: magnetic splitting of ultrashort laser pulses in plasmas
No full textNational Basic Research Program of China [2013CBA01504]; National Natural Science Foundation of China (NSFC) [11129503, 11374210, 11405108, 11421064, 11675108]; National 1000 Youth Talent Project of China; Leverhulme TrustThe Faraday effect, caused by a magnetic-field-induced change in the optical properties, takes place in a vast variety of systems from a single atomic layer of graphenes to huge galaxies. Currently it plays a pivotal role in many applications such as the manipulation of light and the probing of magnetic fields and materials' properties. Basically, this effect causes a polarization rotation of light during its propagation along the magnetic field in a medium. Here, we report an extreme case of the Faraday effect where a linearly polarized ultrashort laser pulse splits in time into two circularly polarized pulses of opposite handedness during its propagation in a highly magnetized plasma. This offers a new degree of freedom for manipulating ultrashort and ultrahigh-power laser pulses. Together with the technologies of ultra-strong magnetic fields, it may pave the way for novel optical devices such as magnetized plasma polarizers. In addition, it may offer a powerful means to measure strong magnetic fields in laser-produced plasmas
Fabrication of "petal effect" surfaces by femtosecond laser-induced forward transfer
No full textNational Key Research and Development Program of China [2016YFB1102400]; National Natural Science Foundation of China [11374316, 61178024]Superhydrophobic adhesive glass surfaces with polystyrene has been obtained via femtosecond laser induced forward transfer (LIFT). Using this facile method, we obtained composite structures on the glass surface, achieving the transformation from hydrophilicity to superhydrophobicity with contact angle from 36.22 degrees on the glass surface to 159.19 degrees on the LIFT modified glass surface. Analogous to the "petal effect", the obtained superhydrophobic surface also shows high adhesion. Furthermore, the wettability of LIFT modified glass surface can be tuned by changing the interval width of laser scanning, which can be explained by the Cassie impregnating wetting model. (C) 2016 Elsevier B.V. All rights reserved
High-order dispersion control of 10-petawatt Ti:sapphire laser facility
No full textNational Basic Research Program of China [2011CB808101]; Strategic Priority Research Program of the Chinese Academy of Sciences [XDB16]; International S&T Cooperation Program of China [2016YFE0119300]; National Natural Science Foundation of China (NSFC) [61521093, 10734080, 60921004, 60908008, 61078037]A grism pair is utilized to control the high-order dispersion of the Shanghai Superintense Ultrafast Lasers Facility, which is a large-scale project aimed at delivering 10-PW laser pulses. We briefly present the characteristics of the laser system and calculate the cumulative B-integral, which determines the nonlinear phase shift influence on material dispersion. Three parameters are selected, grism separation, angle of incidence and slant distance of grating compressor, to determine their optimal values through an iterative searching procedure. Both the numerical and experimental results confirm that the spectral phase distortion is controlled, and the recompressed pulse with a duration of 24 fs is obtained in the single-shot mode. The distributions and stabilities of the pulse duration at different positions of the recompressed beam are also investigated. This approach offers a new feasible solution for the high-order dispersion compensation of femtosecond petawatt laser systems
Numerical investigations of signal-spectrum shaping based on conformal profile theory in optical parametric chirped pulse amplification
No full textNational Natural Science Foundation of China (NSFC) [61378030, 61521093]We proposed a theoretical description and numerical model of signal-spectrum shaping based on conformal profile theory and the three-dimensional coupling wave equations for improving the performance of optical parametric chirped pulse amplification (OPCPA). Using our model, we executed quantitative simulations of signal-spectrum shaping and compared the differences of spatiotemporal amplification characteristics between a shaped signal-spectrum and Gaussian signal-spectrum of an OPCPA based on LiB3O5 near 800 nm. By comparison, we found that the conversion efficiency from pump to signal can be dramatically boosted via signal-spectrum shaping. Meanwhile the amplified-spectrum profile, as well as the Fourier-limited pulse, can be improved significantly. We also found that the spatial spot profiles, for injecting a shaped signal or a Gaussian signal in OPCPA, are nearly the same before the saturation regime and at the maximum conversion efficiency or output energy
Spatial chirp in Ti:sapphire multipass amplifier
No full text100 Talents Program of Chinese Academy of Sciences; National Natural Science Foundation of China [61475169, 61521093, 11127901]; Youth Innovation Promotion Association of Chinese Academy of SciencesThe spatial chirp generated in the Ti:sapphire multipass amplifier is numerically investigated based on the one-dimensional (1D) and two-dimensional (2D) Frantz-Nodvik equations. The simulation indicates that the spatial chirp is induced by the spatially inhomogeneous gain, and it can be almost eliminated by utilization of proper beam profiles and spot sizes of the signal and pump pulses, for example, the pump pulse has a top-hatted beam profile and the signal pulse has a super-Gaussian beam profile with a relatively larger spot size. In this way, a clear understanding of spatial chirp mechanisms in the Ti: sapphire multipass amplifier is proposed, therefore we can effectively almost eliminate the spatial chirp and improve the beam quality of a high-power Ti: sapphire chirped pulse amplifier system
Strong configuration interactions in Be-like ions
No full textNSFC [11374315, 61475168]Strong configuration interactions are observed in Be-like ions between 1s(1)2s(2)nl(1) and 1s(1)2p(2)nl(1). Such configuration interactions not only make a remarkable and systematic difference to the k-shell transition from 1s(1)2p(2)nl(1) to 1s(2)2p(1)nl(1), but they also change the order of the spectral positions between the transitions 1s(1)2p(2)nl(1) - 1s(2)2p(1)nl(1) and 1s(1)2s(1)2p(1)nl(1) - 1s(2)2s(1)nl(1). Including or not including the configuration interaction of 1s(1)2s(2)nl(1) can result in an energy difference of about 6 eV for the 1s(1)2p(2)nl(1) - 1s(2)2p(1)nl(1) transitions of Be-like aluminum. This phenomenon reveals the physical reason behind the existence of differences between the experimental transmission and the theoretical transmission for aluminum plasma in the paper by Zhang et al (2009 Phys. Rev. E 79 016401). For two configurations (KLMf)-L-i-M-j... and (KLMf'')-L-i'-M-j'..., the strongest configuration interactions may appear when the number of electrons in each shell is the same and the parity for each shell is the same
Tunable photoluminescence of CsPbBr3 perovskite quantum dots for light emitting diodes application
No full textNational Natural Science Foundation of China [61520106012, 61574024, 61475169]; Fundamental Research Funds for the Central Universities [106112015CDJZR125511, 106112015CDJXY120001, 106112016CDJCR121222]; SRF [0210002409003]; Advanced and Fundamental Research Funds of Chongqing [cstc2015jcyjA1055, cstc2015jcjA90007]; Chinese Academy SciencesAll-inorganic cesium lead halide (CsPbBr3) perovskite quantum dots (QDs), as one kind of promising materials, have attracted considerable attention in optoelectronic applications. Herein, we synthesized the colloidal CsPbBr3 QDs with tunable photoluminescence (PL) (493-531 nm) by adjusting the reaction temperatures, which revealed narrow emission bandwidths of about 25 nm. The average diameters of the QDs could be adjusted from 7.1 to 12.3 nm as the temperature increased from 100 degrees C to 180 degrees C. Moreover, the radiative lifetimes of CsPbBr3 QDs were measured to be similar to 2 ns, and the single QD fluorescence intensity time trace results demonstrated its suppressed blinking emission. Moreover, green light emitting diodes by using CsPbBr3 QDs tasted on blue LED chips were further fabricated, which provided potential applications in the field of display and lighting technology