1 / 29

Quasi 3D ellipsoidal laser pulse by pulse tailoring and chromatic effect

Quasi 3D ellipsoidal laser pulse by pulse tailoring and chromatic effect. Yuelin Li Advanced Photon Source, Argonne National Laboratory ylli@aps.anl.gov. Some accelerator related laser work at APS. FROG diagnostics of SASE FEL ( Y. Li et al., PRL 89, 234801 (2002); 91, 243602 (2003) )

quasar
Download Presentation

Quasi 3D ellipsoidal laser pulse by pulse tailoring and chromatic effect

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Quasi 3D ellipsoidal laser pulse by pulse tailoring and chromatic effect Yuelin Li Advanced Photon Source, Argonne National Laboratory ylli@aps.anl.gov

  2. Some accelerator related laser work at APS • FROG diagnostics of SASE FEL (Y. Li et al., PRL 89, 234801 (2002); 91, 243602 (2003)) • EO sampling • Off line EO testing experiment: nonlinear EO crystal response (Li et al., Appl. Phys. Lett. 88, 251108 (2006)) • FNAL, NIU and ANL collaboration on EO sampling • Laser beam interaction • Ultrafast X-ray source generation (Li et al, PRST-AB 5, 044701 (2002)) • Ultrafast Gamma-ray generation (Li et. al., APL 88, 021113 (2006)) • Ultrashort positron source (Li et. al., APL 88, 021113 (2006)) • Laser pulse shaping • Transverse pulse shaper for LCLS • 3-D laser pulse shaping (This talk, FEL06, LINAC06, and Li, OL in press) • Laser plasma accelerator • PIC simulation on beam parameter control (Shen, submitted to PRL)

  3. Content • APS Context: APS ERL upgrade • An ellipsoidal beam and its properties • How to generate an ellipsoidal beam • Self evolving • 3D laser pulse shaping • Comparison and Challenges • Accelerating, image/space charge field • Shaping transplant • Zoned lens • References • O.J. Luiten, S.B. van der Geer, M.J. de Loos, F.B. Kiewiet, and M.J. van der Wiel, Phys. Rev. Lett 93, 094802 (2004). • B.J. Claessens, S.B. van der Geer, G.Taban, E.J.D. Vredenbregt, and O.J. Luiten, Phys. Rev. Lett 95, 164801 (2005). • C. Limborg-Deprey and P. Bolton, Nucl. Instrum. Methods A557, 106 (2006). • Y. Li and X. Chang, Proc FEL 2006, Berlin, Aug 26-Sept 1, 2006, paper THPPH053. • J. Rosenzweig, Nucl. Instrum. Methods A557, 87 (2006). • H. Tomizawa et al, Nucl. Instrum. Methods A557, 117 (2006).

  4. The Advanced Photon Source, and its ERL upgrade plan Pulse duration: 100 ps FWHM Challenges (laser related …) High current and low emittance beam must be generated at the injector Drive laser power and pulse shaping Non interceptive, single short measurement of the beam profile Laser technique provides the highest resolution so far Timing must adequate Laser remains an option

  5. What is an ellipsoidal beam • An ellipsoidal beam is an ellipsoid with flat charge density distribution through out • Linear space charge force • Linear to position • Decoupled in trans and longi C. Limborg-Deprey and P. Bolton, Nucl. Instrum. Methods A557, 106 (2006). • Advantages • Compensate for all emittance growth due to space charge effect

  6. Points to ponder • Physics/Engineering • How to generate such beam • To what extant distortion is acceptable • No perfect Ellipsoidal beam can be generated • Any perfect ellipsoidal beam will be distorted • Space charge effect at electron emission • RF and Schottky effect • No optics are perfect • ….. • Economics • Cost versus benefit • 40% to 50% reduction of emittance for LCLS, 15% shorter saturation length will result (Limborg), • from total 33 undulators to 29, save on undulators alone: 4*$474 k (P. Hartog, ANL).

  7. Content • APS Context: APS ERL upgrade • An ellipsoidal beam and its properties • How to generate an ellipsoidal beam • Self evolving • 3D laser pulse shaping • Comparison and Challenges • Accelerating, image/space charge field • Shaping trans plant? • References

  8. Realization of an Ellipsoid I: Luiten Scheme(A ground breaking work) Luiten, “How to realize uniform 3-dimensional ellipsoidal electron bunches”, Phys. Rev. Letters 93, 094802 (2004)

  9. Physical limitations: more details Laser: 100 fs with parabolic transverse distribution with 1 mm radius Cornell DC gun with 500 kV, peak 5MV/m Bazarov, PRST-AB 8, 034202 (2005) • Pro • Easy: Need a short pulse (100 fs) with initial parabolic transverse distribution, no longi shaping needed • Con • Cannot put too many charges • May lack of control on final beam sizes RF gun DC gun Luiten

  10. Realization of an ellipsoidal beam 2: Laser pulse shaping: • Advantages: take a full control • Difficulties • Simultaneous evolving longitudinal and transverse profile • Existing Methods • Pulse stacking (Tomizawa, NIMA 557, 117 (2006), and this workshop) and other manipulation (Limbrorg-Deprey, ibid, 106 ) • Cold electron harvesting (Classen, PRL 95, 164801 (2005) ) • Pulse tailoring with chromatic aberration (this talk) • Eliminated method: Pulse stacking by zoned lens, dynamic focusing using Kerr lensing l t Beam size t

  11. Dynamic focusing effect through Kerr lensing n(t)=n+n2*I(t), n2=2.3810-16 W/cm2 df ~ dn ~ 1% dw /w= L/c * dn/dt, for dn=1% and dt=1 ps, L=1 cm, dw /w =1/3 (b) (a) (c) (a) On-axis laser pulse envelope as a function of the defocusing distance; the intensity as a function of time and radius for a pulse without (b) and with the SPM effect (c). The calculation assumes an f=150 mm lens with R=12 mm and d=5 mm. The pulse wavelength is 0.249 nm with m=15 at laser intensity of 5×1011 W/cm2. Li, Opt Lett, accepted for publication

  12. 3D Laser pulse shaping:phase tailoring and chromatic aberration • Lens formula • Focal length and beam size as a function of frequency • Required beam size as a function of time for ellipsoidal beam • The phase and the amplitude of the pulse are therefore

  13. 3D Laser Pulse shaping: Numerical model • Full wave optics (Fresnel diffraction) adapted from Kempe et. al (JOSA B 9, 1158 (1992)) • Group velocity dispersion and group velocity delay effect considered up to the second order

  14. The resulting 3D laser pulse: Structure due to group delay in optics An ellipsoidal laser pulse generated vis laser pulse tailoring and the chromatic aberration at the focal plane of a 20 mm diameter zoneplate with focal length of 150 mm. The isosurface plots shows the structure at 0.05, 0.1, 0.15 and 0.2 relative intensity. A zone plate has chromatic aberration similar to a lens. Li and Chang, FEL 2006 Li and Chang, LINAC 2006

  15. Performance simulationLongitudinal and transverse emittances

  16. Practical arrangement and challenges Spatial shaper A CPA laser Stretcher Shaper (Phase and amplitude, can be static) Compressor Image relay to Cathode

  17. DAZZLER Or SLIM Oscillator Delay A planned bench test for 800 nm • To demonstrate the feasibility • Need zone plate for 800 nm • Do not need amplifier Zone plate Crystal

  18. Content • APS Context: APS ERL upgrade • An ellipsoidal beam and its properties • How to generate an ellipsoidal beam • Self evolving • 3D laser pulse shaping • Comparison and Challenges • Accelerating, image/space charge field • Shaping transplant? • References

  19. Comparison with self evolving scheme

  20. Challenges and further work • Laser challenge: experiments needed • Bandwidth requirement and flat top input beam • Does phase information survive amplification frequency conversion? • Beam limitation: simulation needed • Integrated optimization with emittance compensation is necessary for determining the usefulness (BAZAROVAND SINCLAIR Phys. Rev. ST Accel. Beams 8, 034202 (2005)) • Charge limitation • Tolerance on beam distortion due to high charge and other effect • Effect of sub structures • Comparison with self evolving scheme is necessary • Adaptive set up

  21. Content • APS Context: APS ERL upgrade • An ellipsoidal beam and its properties • How to generate an ellipsoidal beam • Self evolving • 3D laser pulse shaping • Comparison and Challenges • Accelerating, image/space charge field • Shaping transplant?

  22. Shaping transplant? Sum frequency modulation • The problem: • Pulse too long for self evolving except for a tight cigar beam • Band width too small for direct shaping • Solution: mixing with a shaped laser • Seed beam (shaped) doe not have to be very intense: Poling crystal for high conversion efficiency • Need very detail evaluation to determine if it is practical Shaped Ellipsoidal pulse, w2 +w1 Shaped Ellipsoidal pulse, w1 Long, narrow bandwidth laser pulse, w2 (Spatially shaped to flat top) Frequency mixing crystal

  23. Content • APS Context: APS ERL upgrade • An ellipsoidal beam and its properties • How to generate an ellipsoidal beam • Self evolving • 3D laser pulse shaping • Comparison and Challenges • Accelerating, image/space charge field • Shaping transplant? • Zone lens for 3D

  24. 3-D laser pulse shaping by zoned lens • A zoned lens is a lens with circular zones like a Fresnel lens • Temporal shaping: by controlling the thickness of each zone and its transmission • Transverse shaping: shape and transmission of each zone A Fresnel lens

  25. sn rn f Timing control Dtn tn: zone effective thickness rn: zone radius f: focal length pn: optical path of each zone t

  26. sn rn dn f Intensity profile control Fn: Total flux dn: Zone size, controllable In: input laser distribution, controllable Tn: segment optical transmission, controllable t

  27. sn t rn dn f Spatial profile: ideally By tailoring the shape of each zone, it is possible to control the size and the shape of the beam at the focus, maybe flattop disks with different sizes.

  28. Preliminary results on zoned lens: Temporal shaping is straight forward • A 9-zone lens with an 1.5 ps. 249 nm Gaussian pulse with 150 mm focal length Add delay for each zone Shuffling Original r, 8 micron Time, 18 ps

  29. When off focus by 1.5 mm • Spatial shaping is still difficult Polarization separation Tuning the focii Just off focus R, 0-0.08 mm R, 0-0.08 mm R, 0-0.16 mm

More Related