Dependence of hard x-ray yield on laser pulse parameters in the wavelength-cubed regime

Conversion efficiency and electron temperature scaling laws are experimentally studied in the wavelength-cubed (λ3) regime, where a single-wavelength focus allows low energy pulses incident on a Mo target to produce x rays with excellent efficiency and improved spatial coherence. Focused intensity is varied from 2×1016 to 2×1018 W/cm2. Conversion efficiency and electron temperature are best described by a power law for energy scaling while an exponential law best describes the scaling of these parameters with pulse duration.

[1]  S. C. Prasad,et al.  Laser-based microfocused x-ray source for mammography: feasibility study. , 1997, Medical physics.

[2]  E. Fill,et al.  Spatial characteristics of Kα radiation from weakly relativistic laser plasmas , 2000 .

[3]  F. Pegoraro,et al.  On the design of experiments for the study of relativistic nonlinear optics in the limit of single-cycle pulse duration and single-wavelength spot size , 2002 .

[4]  Antoine Rousse,et al.  Experimental study of the interaction of subpicosecond laser pulses with solid targets of varying initial scale lengths , 1997 .

[5]  A. Tünnermann,et al.  Hard‐x‐ray radiation from short‐pulse laser‐produced plasmas , 1996 .

[6]  Bell,et al.  Collisionless absorption in sharp-edged plasmas. , 1992, Physical review letters.

[7]  Heinrich Schwoerer,et al.  Kα-radiation from relativistic laser-produced plasmas , 2002 .

[8]  Herman,et al.  Intense picosecond X-Ray pulses from laser plasmas by use of nanostructured "Velvet" targets , 2000, Physical review letters.

[9]  Harris,et al.  MeV x-ray generation with a femtosecond laser. , 1992, Physical review letters.

[10]  H Schwoerer,et al.  Optimization of Kalpha bursts for photon energies between 1.7 and 7 keV produced by femtosecond-laser-produced plasmas of different scale length. , 2002, Physical review. E, Statistical, nonlinear, and soft matter physics.

[11]  R. Falcone,et al.  X rays from microstructured targets heated by femtosecond lasers. , 1994, Optics letters.

[12]  Nickles,et al.  Dosimetric measurements of electron and photon yields from solid targets irradiated with 30 fs pulses from a 14 TW laser , 2000, Physical review. E, Statistical physics, plasmas, fluids, and related interdisciplinary topics.

[13]  T. Nishikawa,et al.  Greatly enhanced soft x-ray generation from femtosecond-laser-produced plasma by using a nanohole-alumina target , 1999 .

[14]  Forster,et al.  Yield optimization and time structure of femtosecond laser plasma kalpha sources , 2000, Physical review letters.

[15]  Teubner,et al.  Angle-dependent x-ray emission and resonance absorption in a laser-produced plasma generated by a high intensity ultrashort pulse. , 1993, Physical review letters.

[16]  E. Förster,et al.  Prospects of “water-window” X-ray emission from subpicosecond laser plasmas , 2000 .

[17]  Y. Fujimoto,et al.  ENHANCEMENT OF HARD X-RAY EMISSION FROM A COPPER TARGET BY MULTIPLE SHOTS OF FEMTOSECOND LASER PULSES , 1999 .