Compression of Extreme-Ultraviolet Ultrashort Pulses by Grating Configurations

Fabio Frassetto,Paolo Miotti,Luca Poletto

doi:10.1155/2015/495914

Fabio Frassetto, Paolo Miotti + Show 1 more

Open Access

https://doi.org/10.1155/2015/495914

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Abstract

The design and realization of grating instruments to condition the spectral phase of ultrashort extreme-ultraviolet pulses are discussed. The main application of such configurations is the temporal compression of pulses by compensating the phase chirp and getting close to the Fourier limit. We discuss the two configurations useful for the realization of ultrafast grating compressors, namely, the classical diffraction mount and the off-plane one. The configuration may be applied to free-electron lasers and high-order laser harmonics.

Highlights

The developments in laser technology over the last years lead to the generation of extreme-ultraviolet (XUV) and X-ray coherent ultrashort pulses in the femtosecond and subfemtosecond time scale (1 fs = 10−15 s) [1, 2]
While femtosecond optical lasers have offered unique insights into ultrafast dynamics, short wavelength radiation offers the capability to access and measure the structural arrangement and electronic structure; the advent of high-energy, short-pulse Xray sources based on free-electron lasers (FELs), high-order laser harmonics (HHs), and laser plasmas is making it possible to probe the dynamics of electrons within molecules [3, 4]
The HH spectrum is described as a sequence of peaks corresponding to the odd harmonics of the fundamental laser wavelength and having an intensity distribution characterized by a vast plateau, whose extension is related to the pulse intensity and frequency

Summary

Introduction

Despite the necessity of an additional optical stage, namely, the FEL compressor, this solution allows the use of the whole electron beam charge obtaining a significantly higher number of photons with ultrashort duration For both HHs and FEL facilities, the availability of a XUV and X-ray tunable optical compressor is attractive in order to increase the peak intensity and the time resolution of the source. The first grating is demanded to perform the spectral selection on an intermediate slit; the second grating compensates for the pulse-front tilt of the diffracted beam by equalizing the length of the optical paths, giving a temporal resolution much higher than the single-grating design. The concept may find suitable applications to ultrafast spectroscopy experiments

Grating Geometries for Ultrashort Pulses

Grazing-Incidence Grating Compressor

Grating Compressor Applied to FEL Pulses

XUV Attosecond Compressor

Conclusions