Ablation of polytetrafluoroethylene (Teflon) with femtosecond UV excimer laser pulses.

Experiments on the ablation of undoped polytetrafluoroethylene (Teflon) with 300 fs UV excimer laser pulses at 248 nm are reported for the first time. In contrast to standard excimer laser pulses, these ultrashort pulses ablate Teflon with good edge quality and no signs of thermal damage for fluences down to 0.5 J/cm2 with removal rates on the order of 1 μm per pulse

UV-excimer-laser ablation of polymethylmethacrylate at 248 nm: Characterization of incubation sites with Fourier transform IR- and UV-spectroscopy.

Ultraviolet and Fourier transform infrared (FTIR) spectroscopic experiments with thin films of polymethylmethacrylate (PMMA) are reported. During the incubation with 248 nm excimer laser light or continuous (cw) UV light sources PMMA exhibits a rapidly increasing, broad UV absorption. This is caused by the production of unsaturated species, which are detected in the infrared spectrum of irradiated PMMA films. The spectral data explain the incubation process preceding the ablation of PMMA at 248 nm. Taking advantage of the increased UV absorption, cw light incubated PMMA films can be selectively ablated by standard 308 nm excimer laser pulses

Tunable UV laser photolysis of organometallics with product detection by laser mass spectroscopy: Trimethylaluminum.

We use tunable UV laser light in the region 200–320 nm, produced by frequency doubling the output of a dye laser, for the decomposition of organometallic compounds. This method has been applied to TMA, trimethylaluminum Al(CH3)3. Only the TMA monomer absorbs UV light for λ >220 nm. TMA decomposes by one-photon absorption mainly into two channels: aluminum atoms Al plus organic fragments, and aluminummonomethyl AlCH3 molecules plus organic fragments. The ratio [Al]/[AlCH3] is wavelength dependent. We present a mechanism to explain the photolysis of trimethyl compounds of group III elements (Al, Ga, In)