1 / 29

Characterization of short pulses .

Characterization of short pulses . A. Yartsev. What is good to know about short pulses?. Energy of each pulse Average power Spectrum Spatial distribution Temporal profile Satellites Duration Shape . Energy/Power measurements. fro m pico-Joule to peta-Watt. Physics of detection

aggie
Download Presentation

Characterization of short pulses .

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. Characterization of short pulses. A. Yartsev

  2. What is good to know about short pulses? • Energy of each pulse • Average power • Spectrum • Spatial distribution • Temporal profile • Satellites • Duration • Shape

  3. Energy/Power measurements.from pico-Joule to peta-Watt • Physics of detection • Choice of detector • Linearity • Sensitivity • Spectral response • Response time • Damage

  4. Spectral shape • What do you need the spectrum for? • Sensitivity range. • Calibration of the spectrometer. • Dynamic range. • Optics on the way. • Fibber ”wave guides”.

  5. Beam profile • Assume Gaussian? • Measure power through calibrated pinholes • Blade-edge method • Measure real profile. • 2-D detector: CCD matrix • 1-D array detector • Linearity of response

  6. Temporal profile:What for? • Satellites: quality of amplification, quality of measurements • Pulse duration: FWHM • Instrumental response function • Transform-limited pulse • Pulses of random shape

  7. Electrical (direct) measurements of pulse duration: not fast enough and (very) expensive. • Photodiode: >10 ps (+fast Oscilloscope) • Streak Camera: 100 fs (?), ~1 ps

  8. All-optical methods • Time from distance: 1 fs  0.3 m • Math: correlation function • determines F(t) if G() is measured and F’(t) is known.

  9. Autocorrelation • Interferometric AC • Intensity AC • Single – shot AC • Both F(t) and F’(t) are replica’s of the same function E(t)exp

  10. Interferometric AC • F(t) = E(t)exc[it+i(t)] • I1() =|E(t)exc[it+i(t)] +E(t-)exc[i(t- )+i(t-)]|2dt • I2() =|{E(t)exc[it+i(t)] +E(t-)exc[i(t- )+i(t-)]}2|2dt • First order AC: I1(=0)/I1() = 2 • Second order AC: I2(=0)/I2() = 8

  11. Interferometric AC

  12. Interferometric AC

  13. Limitions of AC • Non-specific: one has assume a particular pulse shape. • Returns only amplitude.

  14. Full-field characterization of femtosecond pulses by spectrumand cross-correlation measurements OPTICS LETTERS / Vol. 24, No. 23 / December 1, 1999 J. W. Nicholson, J. Jasapara, and W. Rudolph F. G. Omenetto and A. J. Taylor

  15. Frequennsy-resolved optical gating FROG Rev. Sci. Instrum., Vol. 68, No. 9, September 1997 R. Trebino, K. W. DeLong, D. N. Fittinghoff, J. N. Sweetser,

  16. Rev. Sci. Instrum., Vol. 68, No. 9, September 1997 R. Trebino, K. W. DeLong, D. N. Fittinghoff, J. N. Sweetser, FROG

  17. Single-shot FROG

  18. FROG

  19. Limitions of FROG • Requirements on set-up: linear detector response, step size, S/N. • Delay-scanning technique. • Measures 2D characteristic – long. • Non-specific: needs a (complicated) retrival to get pulse. • Does not always converge.

  20. X-FROG:spectrally-resolved cross-correlation of an unknown pulse with the reference pulse.

  21. TADPOLE Rev. Sci. Instrum., Vol. 68, No. 9, September 1997 R. Trebino, K. W. DeLong, D. N. Fittinghoff, J. N. Sweetser,

  22. FRPP: pump-probe FROG OPTICS LETTERS / Vol. 27, No. 13 / July 1, 2002 S. Yeremenko, A. Baltuˇska, F. de Haan, M. S. Pshenichnikov, D. A. Wiersma

  23. Self-Referencing Spectral Interferometry for Measuring Ultrashort Optical Pulses SPIDER IEEE J Quant.Elctr. Vol. 35, No. 4, April 1999 C. Iaconis, I.A. Walmsley

  24. SPIDER

  25. Advantages of SPIDER • No moving parts • Direct reconstruction (>1kHz) • Noise immunity • Low sensitivity to detector spectral response • Precision and consistency mesures from data

  26. Limitions of SPIDER • Has to be optimised for a particular time-and spectral range. • Requires calibration. • Very sensitive to delay between pulses – sensitive to alignment.

  27. After SPIDER: ZAP-SPIDER

  28. After SPIDER: SEA-SPIDER E. M. Kosik and A. S. Radunsky I. A. Walmsley C. Dorrer OPTICS LETTERS Vol. 30, No. 3, 2005

  29. After SPIDER: 2DSI OPTICS LETTERS / Vol. 31, No. 13 / July 1, 2006 J. R. Birge, R. Ell, F. X. Kärtner

More Related