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High-efficiency and broadband OPCPA is one of the methods to achieve multi-petawatt or even hundreds petawatt laser system.We demonstrate broadband OPCPA centered near 800 nm in 3D space of YCOB. A maximum conversion efficiency of ~15% and compressed duration of 30.6 fs are achieved for two types of YCOB crystals with PM on the principal and non-principal planes (NPP). The amplified energies and conversion efficiencies of different PM angles confirm that the effective nonlinear coefficient (deff) on the NPP is much higher than that on the principal plane (PP). It is worth studying on PM in 3D space to support higher deff, wider amplification bandwidths, and gain wavelength ranges that cannot be amplified on the PP of nonlinear crystals. OPCPA in the 3D space of nonlinear crystal can be used as amplifiers in petawatt scale or few-cycle high-power laser systems.

Humans currently face an explosion of information. It is estimated that the amount of global information will reach 175 ZB by 2025 and storage of most of this information will not be possible. This is especially true for books, archives, ancient documents, and other warm and cold data, which are extremely difficult to preserve well after a long period of time.In this paper, we propose a multi-layer miniature emulation informationstorage methodto address these issues. A large number of information patterns with a minimum pixel size of 200 nm are transferred to a thin AgInSbTe film using a laser direct writing system. After developing, the information structure is retained and the non-information structure is removed. The final single-layer information structure and the glass substrate, with a thickness of 0.15 mm, simultaneously have high contrast and high transmittance. After being stacked and packaged, 67 layers of glass hard disk are formed and each layer of information can be read directly by an optical microscope.The tolerance of the material to acid, alkali,and temperature is tested; results show that this method has excellent information protection performance. This work provides a promising solution for futureinformation storage.

There have high requirements for the size, shape, and uniformity of the focal spot in direct driving. Both continuous phase plate (CPP) and lens array (LA) can be used for beam shaping and smoothing, but the ability is limited and there are little studies on the cooperation of them. In this paper, the co-design of the CPP and LA was proposed, we theoretically analyze the principle of the co-design and study the design process to achieve better shaping and smoothing performance. Far-field focal spot properties of CPP were obtained by simulation, the optimization by increasing the least spatial period is further proposed to solve the sensitive problem of position error, which has practical application value. The combined design of CPP and LA greatly improves the ability of shaping and smoothing of focal spot, and it is a great significance for beam smoothing in high-power laser system.

Aimingattheproblemthatthetraditionaldetectionmethodscannotsolvetheproblemofmicrodeformationmonitoring,thispaperputsforwardtheresearchofmicrodeformationmonitoringtechnologybasedon3Dlaserscanningtoestablish3Dvisualizationmodel,fromtheselectionofscanningsystem,fielddataacquisition,pointclouddataprocessingAccordingtoransancalgorithmandoptimizedICPalgorithm,athree dimensionalmodelwhichcantrulyreflecttheworkingconditionsofthetowercraneisconstructed,thespaceconversionparametersaresolved,andthethree-dimensionalvisualizationisestablishedComparedwiththetraditionaldeformationmonitoringmethod,thisdetectionmethodhasgreateradvantages.Itrealizesthedeformationmonitoringofsmallfeaturepoints,andcancalculatethedeformationresultsfasterandmoreaccurately.Itreflectstheintuitivenessandinstantaneityof3Dlaserscanning,soastoeliminatetheexistingsafetyhiddentroubleasfaraspossible.

X-ray sources according to the principle of the “free electron laser” (FEL) is able to provide bright radiation with pulses in the femtosecond range. Even nowadays, home-lab X-ray sources with very short pulses in the sub-picosecond range are already available for lab experiments. These laser-based sources need different kinds of optics to direct the emitted X-rays onto the samples. On the one hand, the optics should transfer as much flux as possible and on the other hand, the brilliance and timestructure of the source should not be reduced too much. These requirements are fulfilled with 2-dimensional beam shaping multilayer optics. In this presentation, we introduce the principle of multilayer optics, its application in X-ray static and ultrafast diffraction fields. And we also compare four different types of focusing optics for hard X-rays, suitable for femtosecond X-ray diffraction experiments, using a tabletop femtosecond laser-based plasma source.

The nanosecond-pulsed 100J laser system plays an important role in many fields, such as the pump laser of OPCPA, laser shock processing, laser Thomson scattering, and so on. For the large laser systems, there is an ongoing effort to improve various aspects of system performance, especially the beam quality. We developed the methods to control the beam quality in 100J laser systems. Aiming at improving the near-field beam quality of the laser output, we developed the programmable method to control the liquid crystal spatial light modulator. Considering the gain in the main amplifiers and the spatial nonuniformity through the optical components, we take advantage of the liner amplification model to study near-field compensation algorithm of the fundamental frequency. Moreover, taking the energy nonlinear effect generated during the crystal frequency conversion and the spatial unevenness in the crystal into consideration, we presented the nonlinear transmission model. We performed experiments to study how to improve the near-field beam quality both the fundamental frequency and the tripling harmonic. Because of the limited one-time compensation effect of the fundamental frequency, linear iteration 2-time compensation method is used. It turns out to be that high-quality near-field laser output can be obtained through the optimization algorithm on the basis of near-field compensation of LCSLM. The near-field modulation of the fundamental frequency is 1.26:1, and the near-field modulation of the tripling harmonic is 1.42:1.

Here, we report several effective methods to improve the performance of side pumping combiner in coupling efficiency and temperature characteristics when pumped with large NA pump light. Through increasing the taper ratio of the pump fiber, optimizing the fusion area between the pump fiber and the signal fiber, and selecting the appropriate taper length, the coupling efficiency of the combiner was increased from 91% to 97.3%, and the highest temperature of the combiner was dropped from 67 °C to 53 °C with 1870 W pump light (NA=0.19) injected, which could provide a meaningful reference for the fabrication of side pumping combiner in high power applications. Two home-made side pump combiners have already been used in our previous 2.15 kW, near-diffraction-limited fiber oscillator system, the output power could be further scaled if we utilize the cascaded pump scheme with higher power, higher brightness pump source.

Extreme conditions in the laboratory that correspond to pressures of Giga pascals to Exa pascals are being explored in laboratory with high power lasers. At several giga-pascals, laser process engineering is being developed and pioneered, planetary science at tera-pascals, fusion science at peta-pascals, and quantum vacuum physics at exa-pascals of light pressure. Such a wide range of science, from industrial applications to academic development, is called high energy density science. From this wide range of HED science, I will introduce examples of the activities in Japan such as high-pressure matter and neutron-source development. I will also introduce Japan's high-power laser project as a next stage, which is called “J-EPoCH” and its related laser developments that will promote the development of this high energy density science. The J-EPoCH is the new laser facility to explore a variety of new fields of sciences, based on a 100J/100Hz high power lasers with an active mirror amplification scheme using 10 cm Yb:YAG ceramics pumped by laser diodes. This facility integrates all the state-of-arts high power laser technologies, based on the 160 beams of 100Hz /100J laser module, providing high repetition 10kJ long pulse lasers, 5-20PW short pulse lasers and different kinds of laser plasma accelerators, and laser-driven radiation sources such as x-rays and neutrons. This facility can repetitively access the world of extreme conditions such as quantum vacuum physics, astrophysics, planetary science, high-pressure material science, beam science, laser fusion technology and other academic and industry applications.

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