Pulse Characterization | previous | next | feedback |
Optical pulses and regular optical pulse trains can be characterized in various respects:
- The pulse repetition rate is usually measured with a fast photodiode and an electronic spectrum analyzer.
- The pulse duration can be measured with various methods, e.g. with an autocorrelator or a streak camera. Optical sampling techniques can be used when a shorter reference pulse is available.
- The pulse energy may be measured directly or (for pulse trains) calculated from the average power and repetition rate.
- The peak power may be directly measured with a photodiode or calculated from pulse energy, pulse duration and pulse shape.
- The optical center frequency and spectral shape can be obtained with an optical spectrum analyzer.
- The carrier-envelope offset phase or frequency are of special interest in optical metrology.
- The chirp is related to the spectral phase.
- The timing jitter of a pulse train can be measured with various methods.
- The coherence (e.g. of subsequent pulses) can be characterized e.g. with an interferometer.
There are also methods of complete pulse characterization [4], which reveal the electric field versus time or the complex spectrum (including spectral shape and spectral phase) of ultrashort pulses. The most prominent techniques for this purpose are FROG (frequency-resolved optical gating [2]) and SPIDER (spectral interferometry for direct electric-field reconstruction [7], → spectral interferometry). The results can be visualized in various ways, e.g. with graphs of time- or frequency-dependent functions, or with spectrograms.
Note that apart from the temporal aspect, there is also the spatial aspect. Both aspects are often approximately separated in the sense that the whole spatiotemporal profile of the electric field of a pulse can be specified as the product of two functions, one depending only on time and the other one only on the spatial position. However, for example pulses from Kerr lens mode-locked lasers often exhibit significant coupling of temporal and spatial properties (e.g. a time-dependent beam radius), which makes the complete characterization (and modeling) very challenging.
Bibliography
| [1] | C. Yan and J. C. M. Diels, "Amplitude and phase recording of ultrashort pulses", J. Opt. Soc. Am. B 8 (6), 1259 (1991) |
| [2] | D. Kane and R. Trebino, "Characterization of arbitrary femtosecond pulses using frequency-resolved optical gating", IEEE J. Quantum Electron. 29 (2), 571 (1993) |
| [3] | K. C. Chu et al., "Direct measurement of the spectral phase of femtosecond pulses", Opt. Lett. 20 (8), 904 (1995) |
| [4] | I. A. Walmsley and V. Wong, "Characterization of the electric field of ultrashort optical pulses", J. Opt. Soc. Am. B 13 (11), 2453 (1996) |
| [5] | I. D. Jung et al., "High-dynamic-range characterization of ultrashort pulses", Appl. Phys. B 65, 307 (1997) |
| [6] | R. Trebino et al., "Measuring ultrashort laser pulses in the time-frequency domain using frequency-resolved optical gating", Rev. Sci. Instrum. 68, 3277 (1997) |
| [7] | C. Iaconis and I. A. Walmsley, "Spectral phase interferometry for direct electric-field reconstruction of ultrashort optical pulses", Opt. Lett. 23 (10), 792 (1998) |
| [8] | L. Gallmann et al., "Characterization of sub-6-fs optical pulses with spectral phase interferometry for direct electric-field reconstruction", Opt. Lett. 24 (18), 1314 (1999) |
| [9] | L. Gallmann et al., "Techniques for the characterization of sub-10-fs optical pulses: a comparison", Appl. Phys. B 70, S67 (2000) |
| [10] | L. Gallmann et al., "Spatially resolved amplitude and phase characterization of femtosecond optical pulses", Opt. Lett. 26 (2), 96 (2001) |
| [11] | J. W. Nicholson and W. Rudolph, "Noise sensitivity and accuracy of femtosecond pulse retrieval by phase and intensity from correlation and spectrum only (PICASO)", J. Opt. Soc. Am. B 19 (2), 330 (2002) |
| [12] | E. M. Kosik et al., "Interferometric technique for measuring broadband ultrashort pulses at the sampling limit", Opt. Lett. 30 (3), 326 (2005) |
| [13] | A. S. Wyatt et al., "Sub-10 fs pulse characterization using spatially encoded arrangement for spectral phase interferometry for direct electric field reconstruction", Opt. Lett. 31 (12), 1914 (2006) |
| [14] | C. Dorrer, "High-speed measurements for optical telecommunication systems", IEEE J. Sel. Top. Quantum Electron. 12 (4), 843 (2006) |
See also: pulses, frequency-resolved optical gating, spectral phase, spectral interferometry, carrier-envelope offset
