Carbon dioxide laser synthesis from gaseous precursors has been successfully applied to produce nanosized Al₂O₃ particles. Trimethylaluminum [Al(CH₃)₃] and nitrous‐oxide (N₂O) were used as gas phase reactants. Ethylene (C₂H₄) was added as sensitizer gas. The as‐synthesized powder particles showed considerable carbon contamination and an amorphouslike structure. After thermal treatment at 1200–1400 °C, the powder transformed to hexagonal α‐Al₂O₃ with very low carbon contamination, confirmed by x‐ray diffraction, x‐ray photoelectron spectroscopy, and chemical analysis. The thermally treated powder was composed of spherical single‐crystal nanoparticles with a mean size 〈D〉 of 15–20 nm, as determined by x‐ray diffraction, electron microscopy, and Brunauer–Emmett–Teller specific surface measurements. The laser synthesized Al₂O₃ particles are suitable dispersoids for intermetallic alloy technology.

Second- and third-harmonic generation in single-walled carbon nanotube films is experimentally\ud investigated with the fundamental 1064 nm radiation from a Q-switched Nd:YAG laser.\ud Measurements were performed both on commercially available carbon nanotubes and on samples of\ud carbon nanotubes grown with a catalyst-free method. Third-harmonic generation was observed in\ud both samples while only the sample grown with a catalyst-free method generated a second-harmonic\ud signal. The quantum yield of second- and third-harmonic signal was proven to scale, respectively,\ud with the second and third power of the pump pulse energy up to intensities of 109 W/cm2. © 200