RESONANT HOLOGRAPHIC INTERFEROMETRY MEASUREMENTS OF LASER ABLATION PLUMES IN VACUUM, GAS, AND PLASMA ENVIRONMENTS

Resonant holographic interferometry and dye‐laser‐resonance‐absorption photography have been utilized to investigate the expansion of the laser ablation plumes produced by a KrF excimer laser beam (248 nm) focused onto an aluminum target (≊0.1 cm2, 2–6 J/cm2). Plume expansion was studied in vacuum and in background argon gas pressures of 14 mTorr, 52 mTorr, 210 mTorr, 1 Torr, and 35 Torr. The existing theory for the interpretation of resonant interferograms has been extended to account for Doppler shift effects, the diagnostic laser bandwidth, and the selective absorption of the laser beam. Absolute line densities in the range 4.3×1013–1.0×1015 cm−2 have been measured in the ablation plumes, which imply measured Al neutral densities of up to 1×1015 cm−3. The total number of Al neutral atoms in a plume has been measured to be ≊3×1014, which corresponds to a surface etch rate of ≊1 nm/pulse. Expansion velocities in the range 1.1–1.4 cm/μs were measured for the pressures ≤210 mTorr, while ≊0.3 cm/μs was meas...

[1]  G. Batchelor,et al.  An Introduction to Fluid Dynamics , 1968 .

[2]  R. Dreyfus,et al.  Electronic probe measurements of pulsed copper ablation at 248 nm , 1989 .

[3]  K. Saenger.  On the origin of spatial nonuniformities in the composition of pulsed-laser-deposited films , 1991 .

[4]  R. Gilgenbach,et al.  Laser beam deflection as a probe of laser ablation of materials , 1989 .

[5]  Donald R. Baer,et al.  Consequences of simultaneous exposure of inorganic solids to excimer laser light and an electron beam , 1990 .

[6]  D. Koopman,et al.  Turbulent interaction fronts in counterstreaming laser‐produced plasma studies , 1979 .

[7]  G. Arfken.  Mathematical Methods for Physicists , 1967 .

[8]  G. Tallents.  Two-dimensional ion emission from laser-produced plasmas , 1983 .

[9]  J. Goodman.  Statistical Optics , 1985 .

[10]  R. Lucchese,et al.  Monte-carlo simulations of gas-phase collisions in rapid desorption of molecules from surfaces , 1987 .

[11]  R. Gilgenbach,et al.  Fast, sensitive laser deflection system suitable for transient plasma analysis , 1987 .

[12]  H. B. Nielsen,et al.  Effects of inverse bremsstrahlung in laser-induced plasmas from a graphite surface , 1991 .

[13]  H. Kwok,et al.  TIME-RESOLVED RESONANT ABSORPTION STUDY OF 532-NM LASER-GENERATED PLUMES OVER YBA2CU3O7 TARGETS , 1991 .

[14]  J. Bakos,et al.  Laser blow‐off plasma propagating in low‐pressure gas , 1987 .

[15]  Peter L. G. Ventzek,et al.  Dynamics of excimer laser‐ablated aluminum neutral atom plume measured by dye laser resonance absorption photography , 1991 .

[16]  Roger Kelly,et al.  Reconsidering the mechanisms of laser sputtering with Knudsen-layer formation taken into account , 1988 .

[17]  Joshua E. Rothenberg,et al.  Laser sputtering: Part III. The mechanism of the sputtering of metals low energy densities , 1985 .

[18]  A. Sappey,et al.  Laser-fluorescence diagnostics for condensation in laser-ablated copper plasmas , 1991 .

[19]  J. F. Friichtenicht,et al.  Atomic and ionic beam source utilizing pulsed laser blow off , 1976 .

[20]  B. Weiner,et al.  Laser ablation of aluminum at 193, 248, and 351 nm , 1991 .

[21]  R. Gilgenbach,et al.  Schlieren measurements of the hydrodynamics of excimer laser ablation of polymers in atmospheric pressure gas , 1990 .

[22]  Jeffrey A. Sell,et al.  Laser‐beam deflection measurements and modeling of pulsed laser ablation rate and near‐surface plume densities in vacuum , 1991 .

[24]  R. P. Singhal,et al.  Laser-induced collisional processes in resonant laser ablation of GaAs , 1992 .

[25]  R M Measures.  Spectral line interferometry: a proposed means of selectively measuring the change in the density of a specific atomic population. , 1970, Applied optics.

[26]  C. Vest.  Holographic Interferometry , 1979 .

[27]  D. Geohegan.  Imaging and blackbody emission spectra of particulates generated in the KrF‐laser ablation of BN and YBa2Cu3O7−x , 1993 .

[28]  R. Dreyfus.  Cu0, Cu+, and Cu2 from excimer‐ablated copper , 1991 .

[29]  Fine line aluminum etching in air and in solution using a tunable dye laser , 1989 .

[30]  C. H. Ching,et al.  Resonant holographic interferometry of laser‐ablation plumes , 1993 .

[31]  Bodil Braren,et al.  Direct imaging of the fragments produced during excimer laser ablation of YBa2Cu3O7−δ , 1991 .

[32]  J. Stamper,et al.  Resonant diagnostics of laser‐produced Ba plasmas , 1988 .

[33]  D. Koopman,et al.  Resonant optical schlieren system for plasma flow studies , 1977 .

[34]  D. N. Mashburn,et al.  Characterization of ground‐state neutral and ion transport during laser ablation of Y1Ba2Cu3O7−x using transient optical absorption spectroscopy , 1989 .

[35]  R. Hanson,et al.  Laser‐induced fluorescence imaging of laser‐ablated barium , 1990 .

[36]  J. Jasinski,et al.  Studies of excimer laser ablation of solids using a Michelson interferometer , 1986 .

[37]  Peter L. G. Ventzek,et al.  Schlieren and dye laser resonance absorption photographic investigations of KrF excimer laser-ablated atoms and molecules from polyimide, polyethyleneterephthalate, and aluminum , 1992 .

[38]  C. E. Otis,et al.  Novel geometrical effects observed in debris when polymers are laser sputtered , 1992 .

[39]  A. Sappey,et al.  Planar laser‐induced fluorescence imaging of Cu atom and Cu2 in a condensing laser‐ablated copper plasma plume , 1992 .

[40]  T. S. Baller,et al.  Gas flow dynamics in laser ablation deposition , 1992 .

[41]  G. Jellison,et al.  Resonant shadowgraph and schlieren studies of magnetized laser‐produced plasmas , 1981 .