Europhys. Lett.
Volume 72, Number 2, October 2005
Page(s) 242 - 248
Section Physics of gases, plasmas and electric discharges
Published online 21 September 2005
Europhys. Lett., 72 (2), pp. 242-248 (2005)
DOI: 10.1209/epl/i2005-10237-5

Enhanced $\chem{He}$- $\mth{\alpha}$ emission from "smoked" $\chem{Ti}$ targets irradiated with $\mth{400}$$\un{nm}$, $\mth{45}$$\un{fs}$ laser pulses

F. Y. Khattak1, R. J. Clarke2, E. J. Divall2, M. Edwards3, P. S. Foster2, C. J. Hooker2, A. J. Langley2, P. Mistry3, D. Neely2, O. A. M. B. Percie du Sert1, J. Smith2, C. Spindloe2, G. Tallents3, M. Tolley2 and D. Riley1

1  School of Mathematics and Physics, Queen's University of Belfast University Road, Belfast, BT7 1NN, UK
2  Central Laser Facility, CLRC Rutherford Appleton Laboratory Chilton, Didcot, Oxon, OX11 0QX, UK
3  Department of Physics, University of York - Heslington, York YO10 5DD, UK

received 1 July 2005; accepted in final form 31 August 2005
published online 21 September 2005

We present a study of $\chem{He}$-like 1s2-1s2p line emission from solid and low-density $\chem{Ti}$ targets under $\simeq 45\un{fs}$ laser pulse irradiation with a frequency doubled $\chem{Ti}$:Sapphire laser. By varying the beam spot, the intensity on target was varied from $10^{15}\un{W/cm^2}$ to $10^{19}\un{W/cm^2}$. At best focus, low density "smoked" $\chem{Ti}$ targets yield $\sim 20$ times more $\chem{He}$-$\alpha$ than the foil targets when irradiated at an angle of $45^\circ$ with s-polarized pulses. The duration of $\chem{He}$-$\alpha$ emission from smoked targets, measured with a fast streak camera, was similar to that from $\chem{Ti}$ foils.

52.38.Ph - X-ray, $\gamma$-ray and particle generation.
52.25.Os - Emission, absorption, and scattering of electromagnetic radiation.

© EDP Sciences 2005