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Chen J.,Shanghai JiaoTong University | Zheng Y.,Shanghai JiaoTong University | An N.,Shanghai Institute of Laser Plasma | Chen X.,Shanghai JiaoTong University
Optics Letters | Year: 2015

The scheme of prefocusing to focus sum frequency generation (SFG) without a lens is proposed and experimentally verified in this study. Noncollinear type-I noncritical phasematching SFG to generate a third-harmonic wave with large angular acceptance is presented. The principle of broad angular acceptance and the advantages of this PM configuration are also described in detail. External angular bandwidth of 7.33° for noncollinear SFG was measured in a 2 mm long KH2PO4 (KDP) crystal, which is in reasonably good agreement with the theoretical calculation. The mechanism of broadband SFG and the prefocusing scheme make it possible for the realization of convergent third-harmonic generation without involving a lens, which provides a promising way to avoid damage to optical components during the focusing of high-energy UV light in high-power laser facilities. © 2015 Optical Society of America.

Luo B.,CAEP - China Academy of Engineering Physics | Wang G.,CAEP - China Academy of Engineering Physics | Tan F.,CAEP - China Academy of Engineering Physics | Zhao J.,CAEP - China Academy of Engineering Physics | And 3 more authors.
AIP Advances | Year: 2015

Dynamic behaviors of Zr51Ti5Ni10Cu25Al9 bulk metallic glass were investigated using electric gun and magnetically driven isentropic compression device which provide shock and ramp wave loading respectively. Double-wave structure was observed under shock compression while three-wave structure was observed under ramp compression in 0 ∼ 18GPa. The HEL of Zr51Ti5Ni10Cu25Al9 is 8.97 ± 0.61GPa and IEL is 8.8 ± 0.3GPa, respectively. Strength of Zr51Ti5Ni10Cu25Al9 estimated from HEL is 5.0 ± 0.3GPa while the strength estimated from IEL is 3.6 ± 0.1GPa. Shock wave velocity versus particle velocity curve of Zr51Ti5Ni10Cu25Al9 under shock compression appears to be bilinear and a kink appears at about 18GPa. The Lagrangian sound speed versus particle velocity curve of Zr51Ti5Ni10Cu25Al9 under ramp wave compression exhibits two discontinuances and are divided to three regions: elastic, plastic-I and plastic-II. The first jump-down occurs at elastic-plastic transition and the second appears at about 17GPa. In elastic and plastic-I regions, Lagrangian sound speed increases linearly with particle velocity, respectively. Characteristic response of sound speed in plastic-I region disagree with shock result in the same pressure region(7GPa ∼ 18GPa), but is consistent with shock result at higher pressure(18-110GPa). © 2015 Author(s).

Wang R.-R.,Shanghai Institute of Laser Plasma | Wang W.,Shanghai Institute of Laser Plasma
Guangxue Jingmi Gongcheng/Optics and Precision Engineering | Year: 2014

This paper explores the parameter measurement in laser produced plasma by X-ray line profile spectrscopy. The experiment was conducted on the SG-II laser facility. A 0.35 μm laser beam was focused on a solid chlorine (Cl) target in a vacuum chamber to produce a laser chlorine plasma and the high resolution X-ray elliptical bent crystal spectrograph was used to obtain the X-ray fine structure energy spectrum of the chlorine plasma radiation. The line integrated intensity ratio between H-like Cl (1s-3p) (Lyman-) and He-like Cl (1s2-1s3p) (He-) transitions was used for calculation of the electron temperature. By assuming optically thin, the Lyman-stark broadened profile was utilized to measure the electron density. Obtained experimental results show that the volume averaged electron temperature of Te is about 450 eV and the electron density of Ne is approximately 7.5×1022 cm-3. In addition, the line Full Width at Half Maximum (FWHM) was analyzed. The uncertainty in Ne due to uncertainties in the temperature and the assumed background level was also simply discussed and it is estimated to be within 25%. As a result, the experimental spectroscopic method may become a reference for diagnosing future higher-compression implosions.

Wang R.-R.,Chongqing University | Wang R.-R.,Shanghai Institute of Laser Plasma | Chen W.-M.,Chongqing University | Wang W.,Shanghai Institute of Laser Plasma
Guangxue Jingmi Gongcheng/Optics and Precision Engineering | Year: 2010

The wavelength resolution power of a elliptically curved crystal spectrometer is discussed. After the spectral line profile caused by itself is supposed to be neglected, two main factors effecting on the wavelength resolution power of the spectrometer are analyzed. The first one is mainly that the source center is not on the focus of the ellipsoid and the source size can not be ignored. The other one is that the X-ray is reflected from irregular crystal surface, and it is not an ideal ellipsoid. In order to improve the wavelength measuring precision of the spectrometer, two simulating models are established according to the above mentioned factors. Then the two models are analyzed and the relation between the wavelength resolution power and the exit aperture slit width is presented by digital calculation. Meanwhile, a number of experimental investigations on the wavelength-resolved characteristics of the diagnostic system are conducted under a variety of slit width conditions. The wavelength resolution power affected by the un-ideal crystal surface and the source size is quantitatively analyzed with the spectrometer successfully. The experiments show that obtained results are in agreement with the calculation data. When the exit aperture slit width(2δ) is 10 mm, the full width at half maximum(Δλ) is 3.1×10-3 nm; the 2Δ is 4 mm, and the Δλ is 2.3×10-4 nm. These results prove the validity of simulated results.

Uematsu Y.,Osaka University | Ivancic S.,Laboratory for Laser Energetics | Iwawaki T.,Osaka University | Habara H.,Osaka University | And 3 more authors.
Review of Scientific Instruments | Year: 2014

In order to investigate the intense laser propagation and channel formation in dense plasma, we conducted an experiment with proton deflectometry on the OMEGA EP Laser facility. The proton image was analyzed by tracing the trajectory of mono-energetic protons, which provides understanding the electric and magnetic fields that were generated around the channel. The estimated field strengths (E ∼1011 V/m and B ∼108 G) agree with the predictions from 2D-Particle-in-cell (PIC) simulations, indicating the feasibility of the proton deflectometry technique for over-critical density plasma. © 2014 AIP Publishing LLC.

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