Wavefront measurements in the soft X-ray range

In this article we report a new wavefront sensor, developed at the Laboratoire de Spectroscopie Atomique et Ionique, for a full characterization of soft X-ray beams. The Shack-Hartmann sensor has a theoretical accuracy in the order of at a wavelength around 13 nm. A cartography of the wave-vectors pointing of laser-pumped soft X-ray laser has been achieved. It has shown the presence of many ripples probably coming from plasma instabilities. Capillary discharge soft X-ray laser has been also investigated. For all the pumping configurations, the wavefront is spherical, divergent with a radius of about 6.5 m at 2.5 m from the plasma end. The best wavefront exhibits an error to a perfect wave of 3λ rms. Assuming to focus the beam with a f = 50 mm diffraction-limited mirror, a theoretical focal spot size of 0.5  μ m in diameter have been estimated containing 70% of the incident energy. In that case an intensity of 4 × 10 13  W cm −2 should be achieved.

[1]  Annie Klisnick,et al.  EFFICIENT, HIGH-BRIGHTNESS SOFT-X-RAY LASER AT 21.2 NM , 1997 .

[2]  O'Neill,et al.  Saturated and near-diffraction-limited operation of an XUV laser at 23.6 nm. , 1992, Physical review letters.

[3]  Gerard Jamelot,et al.  Ultraviolet luminescence of CsI and CsCl excited by soft x-ray laser , 1997 .

[4]  M. Kado,et al.  X-ray laser development at Advanced Photon Research Center , 2001 .

[5]  Vyacheslav N. Shlyaptsev,et al.  Short Pulse X-Ray Laser at 32.6 nm Based on Transient Gain in Ne-like Titanium , 1997 .

[6]  Jorge J. Rocca,et al.  Demonstration of a High Average Power Tabletop Soft X-Ray Laser , 1998 .

[7]  J. Rocca,et al.  Focusing of a tabletop soft-x-ray laser beam and laser ablation. , 1999, Optics letters.

[8]  G. Jamelot,et al.  Investigation of strong electric-field induced surface phenomena by soft X–UV laser interferometry , 1998 .

[9]  T. Gustafson,et al.  Diagrammatic evaluation of the density operator for nonlinear optical calculations , 1977 .

[10]  W. Southwell.  Wave-front estimation from wave-front slope measurements , 1980 .

[11]  Osvaldo Daniel Cortázar,et al.  Demonstration of a Discharge Pumped Table-Top Soft-X-Ray Laser [Phys. Rev. Lett. 73, 2192 (1994)] , 1994 .

[12]  Keane,et al.  Demonstration of x-ray amplifiers near the carbon K edge. , 1990, Physical review letters.

[13]  J. A. Plowes,et al.  Refraction compensation by target curvature in X-ray lasers , 1995 .

[14]  D. Chuu,et al.  DIATOMIC MOLECULE UNDER PULSED FIELD : ONE-DIMENSIONAL VERSUS FULL-DIMENSIONAL STUDIES , 1998 .

[15]  A. Kaplan,et al.  Feasibility of x-ray resonant nonlinear effects in plasmas. , 1991, Optics letters.

[16]  G. Jamelot,et al.  Interferograms obtained with a X-ray laser by means of a wavefront division interferometer , 1997 .

[17]  Jorge J. Rocca,et al.  Spatial coherence measurement of a high average power table-top soft X-ray laser , 2001 .

[18]  A Carillon,et al.  Saturated amplification of a collisionally pumped optical-field-ionization soft X-ray laser at 41.8 nm. , 2001, Physical review letters.

[19]  Kenneth A. Goldberg,et al.  Characterization of the accuracy of EUV phase-shifting point diffraction interferometry , 1998, Advanced Lithography.

[20]  J E Trebes,et al.  X-ray laser microscopy of rat sperm nuclei. , 1992, Science.

[21]  D. Garzella,et al.  OPTIMIZING HIGH HARMONIC GENERATION IN ABSORBING GASES : MODEL AND EXPERIMENT , 1999 .

[22]  Dennis L. Matthews,et al.  Effects of line focus width narrowing on amplification in Ne-like Se x-ray laser experiments , 1994, Optics & Photonics.