Analysis of a method of phase measurement of ultrashort pulses in the frequency domain (original) (raw)
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What We Can Learn about Ultrashort Pulses by Linear Optical Methods
Applied Sciences, 2013
Spatiotemporal compression of ultrashort pulses is one of the key issues of chirped pulse amplification (CPA), the most common method to achieve high intensity laser beams. Successful shaping of the temporal envelope and recombination of the spectral components of the broadband pulses need careful alignment of the stretcher-compressor stages. Pulse parameters are required to be measured at the target as well. Several diagnostic techniques have been developed so far for the characterization of ultrashort pulses. Some of these methods utilize nonlinear optical processes, while others based on purely linear optics, in most cases, combined with spectrally resolving device. The goal of this work is to provide a review on the capabilities and limitations of the latter category of the ultrafast diagnostical methods. We feel that the importance of these powerful, easy-to-align, high-precision techniques needs to be emphasized, since their use could gradually improve the efficiency of different CPA systems. We give a general description on the background of spectrally resolved linear interferometry and demonstrate various schematic experimental layouts for the detection of material dispersion, angular dispersion and carrier-envelope phase drift. Precision estimations and discussion of potential applications are also provided.
The Measurement of Ultrashort Laser Pulses
Frontiers in Optics, 2005
In order to measure an event in time, you must use a shorter one. But then, to measure the shorter event, you must use an even shorter one. And so on. So, now, how do you measure the shortest event ever created? Indeed, to see the action in any fast event, whether it's a computer chip switching states, dynamite exploding, or a simple soap bubble popping, requires a strobe light with a shorter duration in order to freeze the action. But then to measure the strobe-light pulse requires a light sensor whose response time is even faster. And then to measure the light-sensor response time requires an even shorter pulse of light. Clearly, this process continues until we arrive at the shortest event ever created. And this event is the ultrashort light pulse. Ultrashort light pulses as short as a few femtoseconds have been generated, and it's now routine to generate pulses less than 100 fs long. And we'd like to be able to measure their electric field vs. time or frequency. Time-and Frequency-Domain Measurements If, to measure a pulse, it's sufficient to measure its intensity and phase in either the time or frequency domains, then it's natural to ask just what measurements can, in fact, be made in each of these domains. And the answer, until recently, was the autocorrelation and spectrum. The frequency domain is the domain of the spectrometer and, of course, what the spectrometer measures is the spectrum. Indeed the typical off-the-shelf spectrometer is sufficient to measure all the spectral structure and extent of most ultrashort pulses in the visible and near-infrared. Fouriertransform spectrometers do so for mid-infrared pulses. And interferometers are available when higher resolution is desired. Unfortunately, until recently, it hasn't been possible to measure the spectral phase. Complex schemes were proposed that yielded the spectral
Journal of The Optical Society of America B-optical Physics, 2003
Ultrashort-pulse characterization techniques, such as the numerous variants of frequency-resolved optical gating (FROG) and spectral phase interferometry for direct electric-field reconstruction, fail to fully determine the relative phases of well-separated frequency components. If well-separated frequency components are also well separated in time, the cross-correlation variants (e.g., XFROG) succeed, but only if short, wellcharacterized gate pulses are used.
JOSA B, 2008
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. We present a discussion, guided by experimental studies, regarding accurate measurement, compression, and shaping of ultrashort laser pulses without autocorrelation or interferometry. Our approach based on phase shaping, multiphoton intrapulse interference phase scan, provides a direct measurement of the spectral phase. Illustrations of this method include new results demonstrating wavelength independence, compatibility with sub-5 fs pulses, and a perfect match for experimental coherent control and biomedical imaging applications.
Ultrashort pulse characterization in amplitude and phase from the IR to the XUV
2005
The work described in this thesis concerns experimental techniques for generating and characterizing ultrafast laser pulses in the XUV and JR. The technique used for characterizing the femtosecond IR laser pulses is spectral interferometry for direct electric field reconstruction (SPIDER). It is extended here to allow, for the first time, every single laser shot to be characterized for a 1 kHz laser system. The large number of acquired laser shots allows for powerful statistical and correlation analysis which prior to this work was not possible. Two such SPIDER setups are used to carry out the most detailed study so far of the input and output of a gas-filled hollow fiber setup for the generation of high-energy, few-cycle pulses. The fluctuations in pulse duration and energy are low; the pulses have a mean FWHM duration of 6.3 fs with a standard deviation of 0.1 fs. The fluctuations of the instantaneous frequency at the pulse peak and their implications for the production of XUV pulses by high-harmonic generation (HHG) are discussed. Few-cycle pulses generated by the new method of spectral broadening through filamentation have been characterized using SPIDER. The measured pulses have a duration of 5.7 fs with an energy of 0.4 mJ. The measurement shows that this new technique can rival the well-established hollow fiber method due to its simplicity and ease of operation. A review of currently proposed as well as already implemented XUV pulse characterization schemes is presented and their suitability for measuring XUV pulses with durations from femtoseconds to attoseconds is discussed.
Linear filter analysis of methods for ultrashort-pulse-shape measurements
Journal of The Optical Society of America B-optical Physics, 1995
We analyze the properties required of a linear interferometer composed of time-stationary and timenonstationary filters and a square-law, integrating detector in order that it may be used for the complete characterization of ultrashort optical pulses. Some general conditions for measurements are formulated for various schemes, and, in particular, time-nonstationary filtering is shown always to be necessary. The roles of both phase-only time nonstationarity and amplitude time gating are investigated in the context of known measurement schemes, and the known nonlinear schemes are shown to be members of a larger class of methods that use amplitude time-nonstationary filters.
Direct measurement of spectral phase for ultrashort laser pulses
Optics Express, 2008
We present an intuitive pulse characterization method that provides an accurate and direct measurement of the spectral phase of ultrashort laser pulses. The method requires the successive imposition of a set of quadratic spectral phase functions on the pulses while recording the corresponding nonlinear spectra. The second-derivative of the unknown spectral phase can be directly visualized and extracted from the experimental 2D contour plot, without any inversion algorithm or mathematical manipulation.
Generation and detection of ultrashort pulses
The exciting field of ultrashort laser optics has experienced tremendous growth since it's inception. One of it's branches that has been of continuous interest is the characterization of ultrashort laser pulses ... Thesis (MSc (Physics))--University of Stellenbosch, 2009.