Space radiation with inherently broadband spectral flux poses a huge danger to astronauts and electronics on aircraft,but it is hard to simulate such feature with conventional radiation sources. Using a tabletop laser...Space radiation with inherently broadband spectral flux poses a huge danger to astronauts and electronics on aircraft,but it is hard to simulate such feature with conventional radiation sources. Using a tabletop laser-plasma accelerator, we can reproduce exponential energy particle beams as similar as possible to these in space radiation. We used such an electron beam to study the electron radiation effects on the surface structure and performance of two-dimensional material(Fe PS3).Energetic electron beam led to bulk sample cleavage and damage between areas of uneven thickness. For the Fe PS3sheet sample, electron radiation transformed it from crystalline state to amorphous state, causing the sample surface to rough.The full widths at the half maximum of characteristic Raman peaks became larger, and the intensities of characteristic Raman peaks became weak or even disappeared dramatically under electron radiation. This trend became more obvious for thinner samples, and this phenomenon was attributed to the cleavage of P–P and P–S bonds, destabilizing the bipyramid structure of [P2S6]4-unit. The results are of great significance for testing the maximum allowable radiation dose for the two-dimensional material, implying that Fe PS3cannot withstand such energetic electron radiation without an essential shield.展开更多
We demonstrate a 100-TW-class femtosecond Ti:sapphire laser running at a repetition rate of 0.1Hz based on a 20TW/10 Hz laser facility (XL-Ⅱ).Pumping the new stage amplifier with a 25J green Nd:glass laser,we success...We demonstrate a 100-TW-class femtosecond Ti:sapphire laser running at a repetition rate of 0.1Hz based on a 20TW/10 Hz laser facility (XL-Ⅱ).Pumping the new stage amplifier with a 25J green Nd:glass laser,we successfully improve the laser energy to 3.4J with duration of 29 fs,corresponding to a peak power of 11 7 TW.展开更多
The temporal profiles of high-power short-pulse lasers reflected from self-induced plasma mirrors（PMs） were measured with high temporal resolution in the sub-picosecond window. The leading front shape of the laser p...The temporal profiles of high-power short-pulse lasers reflected from self-induced plasma mirrors（PMs） were measured with high temporal resolution in the sub-picosecond window. The leading front shape of the laser pulse is found to depend sensitively on the laser fluence on the PM surface. Spectral modulation plays a key role in pulse profile shaping. Our findings will extend our knowledge on properly using PMs.展开更多
The femtosecond laser pulses reflected from the self-induced plasma mirror（PM） surface are characterized. More than two orders of magnitude improvement on intensity contrast both in nanosecond and picosecond tempora...The femtosecond laser pulses reflected from the self-induced plasma mirror（PM） surface are characterized. More than two orders of magnitude improvement on intensity contrast both in nanosecond and picosecond temporal scales are measured. The far-field distribution, i.e., focusability, is measured to degrade in comparison with that without using a PM. Experiments on proton accelerations are performed to test the effect of the balance between degraded focusability and increased reflectivity. Our results show that PM is an effective and robust device to improve laser contrast for applications.展开更多
A speckle pattern is observed when a neodymium-doped yttrium aluminum garnet （Nd：YAG） laser is homogenized by a diffractive optical element （DOE） due to its high spatial coherence. Therefore, a Nd：YAG laser homo...A speckle pattern is observed when a neodymium-doped yttrium aluminum garnet （Nd：YAG） laser is homogenized by a diffractive optical element （DOE） due to its high spatial coherence. Therefore, a Nd：YAG laser homogenized by a DOE was previously considered not suitable to pump a Ti：sapphire laser amplifier. However, we show by experiment and simulation that the speckle structure does not manifest itself in the final amplified Ti：sapphire laser beam. By using the homogenizer, a smooth distribution of the amplified laser beam is obtained. No degradation of the energy, the wavefront, and the temporal characteristics of the amplified laser beam is observed.展开更多
High-order harmonic generation （HOHG） from the inter- actions of relativistically intense laser pulses with solid-density plasma surfaces has been demonstrated as a promising bright coherent x-ray source in the last...High-order harmonic generation （HOHG） from the inter- actions of relativistically intense laser pulses with solid-density plasma surfaces has been demonstrated as a promising bright coherent x-ray source in the last de- cade. In contrast with the harmonic generation from la- ser-gas interactions,展开更多
基金Project supported by the National Natural Science Foundation of China(Grant No.11975308)the Strategic Priority Research Program of Chinese Academy of Sciences(Grant No.XDA25050200)Science Challenge Project(Grant No.TZ2018001)。
文摘Space radiation with inherently broadband spectral flux poses a huge danger to astronauts and electronics on aircraft,but it is hard to simulate such feature with conventional radiation sources. Using a tabletop laser-plasma accelerator, we can reproduce exponential energy particle beams as similar as possible to these in space radiation. We used such an electron beam to study the electron radiation effects on the surface structure and performance of two-dimensional material(Fe PS3).Energetic electron beam led to bulk sample cleavage and damage between areas of uneven thickness. For the Fe PS3sheet sample, electron radiation transformed it from crystalline state to amorphous state, causing the sample surface to rough.The full widths at the half maximum of characteristic Raman peaks became larger, and the intensities of characteristic Raman peaks became weak or even disappeared dramatically under electron radiation. This trend became more obvious for thinner samples, and this phenomenon was attributed to the cleavage of P–P and P–S bonds, destabilizing the bipyramid structure of [P2S6]4-unit. The results are of great significance for testing the maximum allowable radiation dose for the two-dimensional material, implying that Fe PS3cannot withstand such energetic electron radiation without an essential shield.
基金Supported by the National Natural Science Foundation of China under Grant Nos 11074298,91126008,10804128 and 10925421the National Basic Research Program of China under Grant No 2007CB815104the Instrument Developing Project of Chinese Academy of Sciences under Grant No 2010004.
文摘We demonstrate a 100-TW-class femtosecond Ti:sapphire laser running at a repetition rate of 0.1Hz based on a 20TW/10 Hz laser facility (XL-Ⅱ).Pumping the new stage amplifier with a 25J green Nd:glass laser,we successfully improve the laser energy to 3.4J with duration of 29 fs,corresponding to a peak power of 11 7 TW.
基金supported by the National Basic Research Program of China(No.2013CBA01502)the National Natural Science Foundation of China(Nos.11721091,11205100,and 11305103)the National Key Scientific Instrument Development Project(No.2012YQ030142)
文摘The temporal profiles of high-power short-pulse lasers reflected from self-induced plasma mirrors（PMs） were measured with high temporal resolution in the sub-picosecond window. The leading front shape of the laser pulse is found to depend sensitively on the laser fluence on the PM surface. Spectral modulation plays a key role in pulse profile shaping. Our findings will extend our knowledge on properly using PMs.
基金supported by National Basic Research Program of China (No. 2013CBA01502)the National Natural Science Foundation of China (Nos. 11121504, 11205100, and 11305103)the National Key Scientific Instrument Development Project (No. 2012YQ030142)
文摘The femtosecond laser pulses reflected from the self-induced plasma mirror（PM） surface are characterized. More than two orders of magnitude improvement on intensity contrast both in nanosecond and picosecond temporal scales are measured. The far-field distribution, i.e., focusability, is measured to degrade in comparison with that without using a PM. Experiments on proton accelerations are performed to test the effect of the balance between degraded focusability and increased reflectivity. Our results show that PM is an effective and robust device to improve laser contrast for applications.
基金This work was supported by the National Basic Research Program of China （No. 2013CBA01501） and the National Natural Science Foundation of China （Nos. 11135012 and 11375262）.
文摘A speckle pattern is observed when a neodymium-doped yttrium aluminum garnet （Nd：YAG） laser is homogenized by a diffractive optical element （DOE） due to its high spatial coherence. Therefore, a Nd：YAG laser homogenized by a DOE was previously considered not suitable to pump a Ti：sapphire laser amplifier. However, we show by experiment and simulation that the speckle structure does not manifest itself in the final amplified Ti：sapphire laser beam. By using the homogenizer, a smooth distribution of the amplified laser beam is obtained. No degradation of the energy, the wavefront, and the temporal characteristics of the amplified laser beam is observed.
基金supported by the National Basic Research Program of China(No.2013CBA01502)the National Natural Science Foundation of China(Nos.11305103,11374209,11374210,and 11205100)+1 种基金the Natural Science Foundation of Shanghai(No.13ZR1456300)the International Science&Technology Cooperation Program of China(No.2014DFG02330)
文摘High-order harmonic generation （HOHG） from the inter- actions of relativistically intense laser pulses with solid-density plasma surfaces has been demonstrated as a promising bright coherent x-ray source in the last de- cade. In contrast with the harmonic generation from la- ser-gas interactions,
