Using phase retrieval to measure the intensity and phase of ultrashort pulses: Frequency-resolved optical gating

Journal Article · Sat May 01 00:00:00 EDT 1993 · Journal of the Optical Society of America, Part A: Optics and Image Science; (United States)

DOI:https://doi.org/10.1364/JOSAA.10.001101· OSTI ID:6340064

Trebino, R ^[1]; Kane, D J ^[2]

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1. Sandia National Laboratories, Livermore, CA (United States)
2. Southwest Sciences, Inc., Santa Fe, NM (United States)

The authors recently introduced a new technique, frequency-resolved optical gating (FROG). For directly determining the full intensity I(t) and phase [var phi](t) of a single femtosecond pulse. By using almost any instantaneous nonlinear-optical interaction of two replicas of the ultrashort pulse to be measured, FROG involves measuring the spectrum of the signal pulse as a function of the delay between the replicas. The resulting trace of intensity versus frequency and delay yields an intuitive display of the pulse that is similar to the pulse spectrogram, except that the gate is a function of the pulse to be measured. The problem of inverting the FROG trace to obtain the pulse intensity and phase can also be considered a complex two-dimensional phase-retrieval problem. As a result, the FROG trace yields, in principle, an essentially unique pulse intensity and phase. It is shown that this is also the case in practice. An iterative-Fourier-transform algorithm is presented for inverting the FROG trace. The algorithm is unusual in its use of a novel constraint: the mathematical form of the signal field. Without the use of a support constraint, the algorithm performs quite well in practice, even for pulses with serious phase distortions and for experimental data with noise, although it occasionally stagnates when pulses with large intensity fluctuations are used. 49 refs., 15 figs.

• OSTI ID: 6340064
• Journal Information: Journal of the Optical Society of America, Part A: Optics and Image Science; (United States), Vol. 10:5; ISSN 0740-3232
• Country of Publication: United States
• Language: English

Related Subjects

42 ENGINEERING
47 OTHER INSTRUMENTATION
99 GENERAL AND MISCELLANEOUS//MATHEMATICS, COMPUTING, AND INFORMATION SCIENCE
ELECTROMAGNETIC PULSES
NONLINEAR OPTICS
PHASE SHIFT
ALGORITHMS
RADIANT FLUX DENSITY
FOURIER TRANSFORMATION
ITERATIVE METHODS
THEORETICAL DATA
CALCULATION METHODS
DATA
ELECTROMAGNETIC RADIATION
FLUX DENSITY
INFORMATION
INTEGRAL TRANSFORMATIONS
MATHEMATICAL LOGIC
NUMERICAL DATA
OPTICS
PULSES
RADIATIONS
TRANSFORMATIONS
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440600 - Optical Instrumentation- (1990-)
990200 - Mathematics & Computers