Comparison of k’’ (gvd/mm) for water measured by MIIPS and whitelight interferometry and calculated using the Sellmeier and NIST dispersion formulas. The upper graph shows the difference of the corresponding values with respect to those calculated using the Sellmeier dispersion formula. A temperature of 21.5 ºC was used for both calculations. Appl. Opt. 46, 8394 (2007)

(a) Multiple independent comb shaping (MICS) concept applied to the generation of a pair of delayed optical pulses. The two pulses, one at zero delay and the other at delay t, are created by encoding a piecewise phase mask across the spectrum. This phase is an alternating superposition of continuous phase functions applied to two independent combs that sample the laser spectrum. (b) Intensity and interferometric autocorrelation spectrograms. (c) Spectrally integrated intensity and interferometric autocorrelations. (d) Complex waveform generation: a 3+1 pulse sequence, with the first pulse having third-order dispersion of -5000 fs3, the second with second-order dispersion of +200 fs2, and the third being transform limited (TL). The fourth TL pulse is scanned to produce a cross-correlation trace. Opt. Express 17, 14351-61 (2009)

Ultrafast Lasers and Optics

The inherent brevity of ultrashort laser pulses prevents a direct measurement of their electric field as a function of time therefore different approaches based on autocorrelation have been used to characterize them. Our approach based on phase shaping, multiphoton intrapulse interference phase scan (MIIPS), provides a direct measurement of the spectral phase. A schematic of this approach is seen at right.

Accurate measurement, compression, and shaping of ultrashort laser pulses without autocorrelation or interferometry thus becomes possible. MIIPS has demonstrated to be wavelength independent, compatible with sub-5 fs pulses, and a perfect match for experimental coherent control and biomedical imaging applications.

Publications: 183, 121, 103, 85, 78, 77, 73, 68, 65, 62


The use of femtosecond lasers requires accurate measurements of the dispersive properties of media. MIIPS is able to measure the second- and third-order dispersion of different optical media with high precision and accuracy. At right is a comparison of the dispersion of water measured and predicted with different techniques.

Publication: 178, 164, 161, 129, 114


Multiple Independent Comb Shaping (MICS) is an intuitive versatile technique for the synthesis of optical pulse sequences where the input laser spectrum is viewed as a superposition of independent but interlaced combs assigned to different sub-pulses. The devised concept enables intuitive programming of complex multi-pulse waveforms via one-dimensional phase-only shaping. Using this approach, we perform self-referenced cross-correlation measurements of various optical waveforms and demonstrate the generation and coding of shaped pulse sequences.

Publication: 145, 138