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Effects of carrier envelope phase on single shot XUV super continuum generation

Effects of carrier envelope phase on single shot XUV super continuum generation. Mahendra Man Shakya, Steve Gilbertson, Chris Nakamura, Chengquan Li, Eric Moon, Zuoliang Duan, Janson Tacket, Shambhu Ghimire and Zenghu Chang. 200. Why do we need attosecond pulses?. as. ps. fs. 10 -18 s.

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Effects of carrier envelope phase on single shot XUV super continuum generation

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  1. Effects of carrier envelope phase on single shot XUV supercontinuum generation Mahendra Man Shakya, Steve Gilbertson, Chris Nakamura, Chengquan Li, Eric Moon, Zuoliang Duan, Janson Tacket, Shambhu Ghimire and Zenghu Chang 200

  2. Why do we need attosecond pulses? as ps fs 10-18 s 10-15 s 10-12 s Time Circulation Vibration Rotation

  3. Elaser t What Was Before reported?Single attosecond pulse at cutoff • Laser pulse: 5 fs, 0.75mm Single attosecond pulse(250 as) 85 eV 135 ev Attosecond pulse train BALTU KA et al., Nature 421, 611( 2003)

  4. Our Goal • To study dynamics of electron in atoms and molecules using pump-probe technique with the pulse as short as25 attosecond (one atomic unit) generated from plateau region of XUV spectrum. • To Study effect of CE phase change on the dynamics of electrons in atoms. • To determine the absolute CE phase from XUV Spectrum

  5. What is the advantage of XUV single shot over f-2f spectrometer ? • f-2f set up measures the relative CE phase change . • But it is possible to determine absolute phase from XUV by investigating shot to shot variation of CE phase with polarization gated input.

  6. What is the polarization gating??? e- Right Circular Pulse e- e- Td Ellipticity dependent pulse Left Circular Pulse V. T. Platonenko and V. V. Strelkov J. Opt. Soc. Am. B 16, 435 (1999)

  7. Our Method: Generation of pulses with a time-dependent ellipticity Using Quartz plate Optic axis Optic axis Ellipticity-dependent pulse Quartz Plate l/4 Waveplate

  8. Polarization gate width : Simplified Formula and Example Z. Chang, PRA (2004)

  9. Major problem: Less number of photons Our Effort: • Phase Matched Pressure. • Small Diverging Angle of XUV • Aluminum Filter Shield (Design)

  10. Retractable Mirror Aluminum Filter Diffraction Grating Gas Cell Parabolic Mirror MCP2 nA MCP1 CCD2 Our Design: Higher Efficiency CCD1

  11. Phase matching

  12. Phase matched Plot

  13. From phase matching pressure to phase mismatching pressure 20Torr 30Torr 55 Torr 80Torr 60 Torr 125Torr eV 35.65 38.75 57.35 41.85 45 48 54.25 51 8Jan05_Sun

  14. Phase matching

  15. Measurement of half the diverging angle of the XUV beam Focus Diffraction Grating Retractable Mirror Aluminum Filter Diffraction Grating Gas Cell 8.1mrads Parabolic Mirror 21.7mrads 1.35cm MCP2 nA MCP1 CCD2 W0 D=0.4cm W=1.3cm D=0.4cm

  16. Measurement of half the diverging angle of the XUV beam Focus Diffraction Grating 8.1mrads 21.7mrads 1.35cm W0 D=0.4cm W=1.3cm D=0.4cm

  17. What do we expect to see with polarization gated input?? -spatial analogy Single electron – ion Collision Single slit Many Electron-ion Collision Multi-slit

  18. CE phase Zero Degree ( Double slits analogy)

  19. CE phase 90 Degree ( Single Slit analogy)

  20. Linear and Long pulse ( 25fs) Harmonic spectrum (Multi- Slits analogy)

  21. Discrete harmonics with linear and long pulse(25fs) input

  22. Linear and Short pulse (6fs) spectrum before polarization gating was applied ( Reduced Slit Number )

  23. Discrete but broad spectral width with linear 6fs input before gating( reduced slit analogy)

  24. Super continuum with Polarization Gated input at 100 shots (Single Slit Analogy)

  25. Super continuum with polarization gated input at 100 shot (Single slit analogy)

  26. MCP2 Retractable Mirror Aluminum Filter Diffraction Grating Phosphor Screen Gas Cell Parabolic Mirror hν CCD1 e- e- MCP2 nA nA MCP2 MCP1 CCD2 hν Phosphor Screen e- nA Measurement of The Number of photons per pulse

  27. Effect of CE Phase Change on XUV Spectrum

  28. Single shot spectrum with CE phase unlocked 2’28” 2’20” 1’23” 1’06” 0’50” 0’35” 0’17” 0’0”

  29. Single Shot Super continuum with CE Phase locked 4Dec05_Sun

  30. Summary • Dependence of the photon flux of polarization gated high harmonics on the target gas pressure was investigated. • Highest number of photons was estimated to be ~104 , which was enough to run single shot experiment. • We observed effect of CE phase on XUV spectra, which could be applied as a “phase meter”.

  31. MCP2 Phosphor Screen hν e- e- nA Measurement of Number of photons per pulse

  32. Required Beam Size to eliminate photon loss Collimating mirror f = 1.5 m D=? 1.3 cm =1.3cm Focusing mirror f = 250 mm Required D is Required D is D=0.4cm 1.3 cm

  33. Measurement of half the diverging angle of the XUV beam Focus Diffraction Grating 8.1mrads 21.7mrads 1.35cm W0 D=0.4cm W=1.3cm D=0.4cm

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