M S Tillack et al 2004 Nanotechnology 15 390 doi:10.1088/0957-4484/15/3/028
M S Tillack, D W Blair and S S Harilal
Show affiliationsAblation plumes caused by short-pulse laser irradiation provide conditions which are well suited to the formation of nanoclusters. The high saturation ratios and presence of ionization lead to extraordinarily high nucleation rates and small critical radii. We have explored the homogeneous nucleation and heterogeneous growth of condensates from Si targets expanding into a low-pressure He ambient using a Nd:YAG laser with a pulse length of 8 ns, wavelength of 532 nm and intensities in the range of 5 × 107–5 × 109 W cm−2. Clusters in the range of 5–50 nm have been produced. In the highly dynamic, non-linear regime of short-pulse laser–matter interactions, plume evolution and condensation processes are strongly coupled and difficult to predict accurately from modelling alone. Both numerical predictions and experimental results were used to quantify the competing effects of ionization and supersaturation. The results suggest a dominant influence of ionization for nearly all intensities above the ablation threshold.
61.80.Ba Ultraviolet, visible, and infrared radiation effects (including laser radiation)
52.70.Kz Optical (ultraviolet, visible, infrared) measurements
51.70.+f Optical and dielectric properties
42.60.Jf Beam characteristics: profile, intensity, and power; spatial pattern formation
Instrumentation and measurement
Issue 3 (March 2004)
Received 23 August 2003, in final form 13 November 2003
Published 21 January 2004
M S Tillack et al 2004 Nanotechnology 15 390
J -A Schweitz 1977 J. Phys. A: Math. Gen. 10 517
A. Karch et al JHEP11(2009)017
J-P Antoine 2004 J. Phys. A: Math. Gen. 37 1463
V Alvarez-Valado et al 2009 Metrologia 46 637
J Boehm et al 1986 J. Phys. D: Appl. Phys. 19 L97
R Sato 1996 J. Phys.: Condens. Matter 8 8363
M Geddes 1984 Phys. Educ. 19 268
Pran Nath and Raza M. Syed JHEP02(2006)022
M. Brambilla and A. Cardinali 1992 Nucl. Fusion 32 465