Research on SN contrast ratio for SGII-PW laser System

1. Research on SN contrast ratio for SGII-PW laser System 2014/8/14 Jianqiang Zhu, Guang Xu, Xiaoping Ouyang and Xinglong Xie

2. Outline • Introduction • SG-II PW laser facility and recent achievements • SN contrast ratio study in SG-II PW laser facility • Programs of ultra short lasers in NLPLP • Conclusion

3. Outline • Introduction • SG-II PW laser facility and recent achievements • SN contrast ratio study in SG-II PW laser facility • Programs of ultra short lasers in NLPLP • Conclusion

4. Introduction—from Shanghai to Tel-Aviv Tel-Aviv Israel Shanghai China

5. Development of Lab YEAR 1986 the NLHP Lab was founded 1987 SG-I facility was accepted with 1.6kJ/1ns(1ω) 1995 SG-II facility was began to launch 2001 SG-II facility was accepted with 6kJ/1ns(1ω 2006 SG-II multi-functional high-power laser system(the 9th beam) was accepted with 5kJ/3ns(1ω) 2007 SG-II-up facility was officially launched SG-II-up facility will be completed and reach 24KJ/3ns(3ω)) and the 9th beam will reach 1KJ/(1-10)ps(1ω). 2014

6. Since 1964 Development of Facility ○40mm ○70mm ○200mm ○250mm ○350mm □350mm Aperture 8beam SG-ⅡUp (～2012) 1beam 8beam 9th beam (2006) SG-Ⅱ (2000) 2 beam 6 beam SG-Ⅰ (1986) 1 beam 6 beams (1980) (1973) 24kJ/3ω/3ns 40kJ/1ω/3ns ~1kJ/~ps 5kJ/3ω/3ns 3kJ/3ω/1ns 6kJ/1ω/1ns 1.6kJ/1ω/1ns 180J/1ω 50J/1ω

7. About SG-II Facility 8 Pulsed Laser Beams Energy 6KJ/1W/1ns 2KJ/3W/1ns 1KJ/1W/130ps

8. About SG-II Facility 9th Pulsed Laser Beam Energy 5KJ/1W/3ns 3KJ/3W/3ns 300J/1W/100ps

9. About SG-II Facility ICF Target Chamber X-ray Target Chamber 9th Laser Beams Injection Precision 20μm(rms)

10. About SG-II Facility No.9 Laser Beam injecting ICF Target Chamber and X-ray Target Chamber have 3 styles.

11. SG-II Facility Experiment Function SG-II has achieved about 4000 shots since 2000, the success rate more than 80% Neutron production 4×10９ 1000 times target compression • Physical experiments： • Black cavity radiation physics • Implosion physics • Hydrodynamic instability • Radiation opacity • Radiation-driven shock wave • Temperature and density plasma physics • Production and application of X-Ray

12. 1ns 5 4 3 2 light 1 t Drive laser 310m CH sphere pole SG-II Facility Physical Experiment Cylindrical target compression and hot spot status diagnosis tests Physicists diagnosed the self-luminous time-integration image when the cylindrical target was directly driven by 8 laser beams or when the spherical target implode inside by using the 2-3keV KB low-energy band of KB imaging system and observed obvious extreme intensity distribution at the center of both chambers.

13. SG-II Facility Physical Experiment Nature Physics 6，DOI Number:10.1038/ NPHYS1790, 2010, 10

14. Experimental results of collision-free shock wave SG-II Facility Physical Experiment Under the support of “Joint research on high energy density physics with Japan and South Korea”, the three parties successfully carried out collision-free shock wave experiments on SGⅡ device on September 16, which provides important evidence on the cause of collision-free shock wave phenomena in astrophysics. The output laser quality has reached international advanced level. • Results published on “Plasma Physics and Controlled Fusion”(2008, 50, 124057)and was invited to the 8th Pacific Rim International Conference on Laser and Optoelectronics report. • The experimental results were included in the “Large scientific facilities of the Chinese Academy of Sciences” (2008-2009）

15. Summary ——SG-II facility is an important platform for inertial confinement fusion (ICF) research and national physical researches, which also represents the general technology achievement in high power laser physics. ——SG-II facility have 9 laser beams, provide: 8 laser beams: 750J/beam/1w/1ns, 250J/beam/3w/1ns, 120J/beam/1w/130ps No.9 laser beam: 5000J/beam/1w/3ns, 3000J/beam/3w/3ns 500J/beam/1w/300ps 10J/beam/1w or 3w/30ps ——SG-II up facility will be completed and reach 24KJ/3ns(3ω)) ，and the 9th beam will reach 1KJ/(1-10)ps(1ω).

16. Outline • Introduction • SG-II PW laser facility and recent achievements • SN contrast ratio study in SG-II PW laser facility • Programs of ultra short lasers in NLPLP • Conclusion

17. PW laser in SGII-UP facility Ns pulses 8 beams Energy: 3000J/beam at 351nm Pulse width: 3ns Ps pulse 1 beams Energy: 1000J at 1053nm Pulse width: 1~10ps Intensity: 1020W/cm2 Contrast: 106~108

18. Introduction – fast ignition and PW lasers Fast ignition is a new approach to inertial confinement fusion.

19. Oscillator Stretcher OPCPA Amplifier Compressor Chamber 1~10ps 230fs 3.2ns 1.7ns PW laser in SGII-UP facility

20. Recent achievements in SG-II PW laser facility Pulse energy : 380J Time width: 5ps Beam size: 105*290mm ( elliptical) Focal spot: 1.3DL(2013年实验数据:E50%=5.1DL) Grating size: 300*340mm( 1740g/mm)

21. Outline • Introduction • SG-II PW laser facility and recent achievements • SN contrast ratio study in SG-II PW laser facility • SN contrast ratio simulations for PW laser pulses • SN contrast ratio test for SG-II PW laser • SN contrast ratio improvement for SG-II PW laser • Programs of ultra short lasers in NLPLP • Conclusion

22. SN contrast ratio Simulations for PW laser pulses Pre-pulse from oscillator Pedestal from stretcher Satellite from non-linear chirped Different noise before main pulse

23. Time delay Phase plane Time delay SHG Detector Cross-correlation Pulse contrast test Schematic of cross-correlation 55º Measurement for repetition pulse, time delay is caused by movement of delaying mirror pairs. Measurement for single shot pulse, time delay is caused by tilting of two wide beams.

24. SN contrast ratio test for SG-II PW laser For repetition pulses • PsSNR1500 • Dynamic range: 108@1mJ,10ps ≥1010@fs pulse • Time range: 1500ps • Time resolution: 20fs Chinese Journal of Lasers, 2009, Vol 36(3), pp742

25. SN contrast ratio test for SG-II PW laser For single shot pulse • PsContrast80 • Dynamic range: 106@1mJ,10ps ≥108@1ms 1ps • Time range: 80ps • Time resolution: 1ps Peak of signal: 1×107mV，Noise: 7mV Tested under pulse with 1mJ,10ps

26. Final test for SG-II PW laser Parabolic mirror in target chambe Large aperture calorimeter 1700J/1.7ns G1 G4 Compressor G2 T=1% Sampling mirror G3 Down-collimator T=2% Lens2 Lens1 8:1 Diagnostics for SGII Ninth Beam Sampling energy Pulse contrast BS2 BS1 Pulse width Far field BS3

27. SN contrast ratio test for SG-II PW laser Test on PW laser: PW laser: 100J, 5ps Compressed Pulse Diagnostics

28. SN contrast ratio improvement for SG-II PW laser 1 SN contrast ratio control in pulse stretcher 2 SN contrast ratio control in OPCPA pre-amplifier 3 Spectrum shape for chirped laser pulse 4 Controlling smoothness of the optics surface 5 Plasma mirror

29. Grating R2 R1 SN contrast ratio control in pulse stretcher Pulse contrast by curvature error Pulse contrast by tilt error Offner Stretcher (ΔS=R1/2-R2) 1)Pulse contrast can be improved by decreasing tolerance of mirror’s curvature in stretcher. 2) Pulse contrast can be improved by decreasing tolerance of mirror’s tilt in stretcher

30. SN contrast ratio control in OPCPA pre-amplifier Pump pulse Chirped pulse Non-collinear mode in OPCPA Time lag between pump laser and signal • Noise from parameter fluorescence is avoid by non-collinear(1-3°) mode in OPCPA. • pulse contrast ratio can be improved by time lag between pump laser and signal. In this method, noise before main pulse of signal will not be amplified.

31. SN contrast ratio control in OPCPA pre-amplifier In OMEGA EP facility, fluorescence Noise is undetectable after the main amplifier chain

32. SN contrast ratio control in OPCPA pre-amplifier fluorescence Noise test and analysis 1.3ns Pulse contrast ratio improvement is verified in experiment in OMEGA EP

33. SN contrast ratio control in OPCPA pre-amplifier Time delay between pump pulse and chirped pulse in OPCPA

34. Spectrum shape for chirped laser pulse input output Gain narrowing in Nd glass amplifier Pulse contrast for 1ps pulse (simulation) 1) Gain narrowing in Nd glass amplifier will distort temporal shape and spectral shape of chirped pulse. 2) Distorted pulse shape contained more noise than Gaussian pulse shape.

35. controlling smoothness of the optics surface Surface smoothing of optics Roughness noise (GRMS) of optic surface Pulse contrast by roughness For SN contrast ratio higher than 10-12:1, the GRMS of the roughness of optic surface should be smaller than λ/75/cm @ 633nm

36. Parabolic mirror 1 φ30mm Ps pulse 10mJ, 12ps f=30mm PM1 I=1016W/cm2 PM2 f=30mm PsContrast80 Parabolic mirror 2 Plasma mirror Schematic of double PMs experiment Plasma mirror is considered in our PW laser. It is designed as the following figure. And it will be tested under ps pulse laser in the future.

37. Plasma mirror design Pulse contrast improved by Double plasma mirrors (DPM) Opitcs Letters Vol.32(3), pp310 Contrast is improved 104 in France (2007) and in German (2013) .

38. Plasma mirror design • Threshold ：1012W/cm2 • Saturated power：1015W/cm2 • Energy density for high quality beam：90J/cm2 • Maximum reflection： R=68% • Status: under design

39. Outline • Introduction • SG-II PW laser facility and recent achievements • SN contrast ratio study in SG-II PW laser facility • Programs of ultra short lasers in NLPLP • Conclusion

40. Programs of ultra short lasers in NLPLP Project of 10PW 808nm Laser 10PW (30fs/300J) 808nm laser project has been supported Goals: In the following 2 or 3 years – 10 PW facility provided for fundamental physical experiments

41. Schematic for 10PW ultra short laser design Three stages: （1）front end: pulse energy 150mJ、spectrum 80nm,chirped pulse width 2.0ns. For high SN contrast ratio reason, we chose OPCPA technology （2）pre-amplification Beam size 100mm，chirped pulse width 2.0ns,spectrum 50nm, pulse energy 10J. For the following reasons we chose the CPA technology • Commercial laser can provide 1PW output • Stability for engineering usage • Maturation of the technology • SIOM has built a 1PW CPA laser system that can be a base

42. Schematic for 10PW ultra short laser design （3）Energy amplification for 10PW output Beam size 200mm， LBO crystal PUMP source: width 3.0ns，1500J 527nm OUTPUT: pulse energy 300J，spectrum 45-50nm Compressed pulse: 20-30 fs. In the design of the main amplification, we chose OPCPA technology for the following reasons: • OPCPA technology bears high SN contrast pulses • And also can decease the uncompressed noise by nonlinear process. • When goes to large beam size, CPA technology has low efficiency and noise will be increased by the transverse oscillation. • For engineering reason, we can use the SG-II and the Ninth Beam as the PUMP source for OPCPA design.

43. Energy fluence design for 10PW laser Pre-OPCPA CPA OPCPA 1-2J 20J 150mJ 300J CPA-II OPCPA-I OPCPA-IV CPA-III 1500J 750mJ 200J 0.5GW/cm2 1.5GW/cm2 0.8GW/cm2 1.5J（50%） 3000J(50%) 400J(50%)

44. 14m PUMP 5m Φ8mm,0.75J 3ns,平顶 Φ55mm,65J 3ns,平顶 Φ110mm,270J 3ns,flat OPCPA 1.5m*4m 展宽器 1.5m*3.5m CPA Φ50mm,10J F=0.73m 6.1m S=0.8m 1m F=1.3m 2.6m S=1.5m 2m Φ100mm,40J The pump beams of SG-II laser 1.5m 1.5m Φ6mm,150mJ Layout of 10PW laser amplification chain

45. Φ260mm,1500J,2ns (from 9th beam) Φ400mm,300J S=1.7 5.8m 4.5m F=2m 4.25m 2m F=1.6m 3.7m S=1.5m 4.2m 7m 4.5m Φ230mm,300J

46. Outline • Introduction • SG-II PW laser facility and recent achievements • SN contrast ratio study in SG-II PW laser facility • Programs of ultra short lasers in NLPLP • Conclusion

47. Conclusion • In conclusion • SG-II PW laser and recent progress are introduced. • Factors that affect the SN contrast ratio of SG-II PW laser are discussed. • We have measured the SN contrast ratio for the output of SG-II PW laser at 100J@5ps. • Program of ultra short and ultra high power 10 PW laser has been designed based on SG-II and SG-Ninth beam, our goal is in three to five years the laser can be provided for fundamental physical experiments.

48. Thank You for Your Attention !