An Experimental Investigation On Resonant Laser Ablation Of Iron-containing Metal Sample Ranged From 281.5 To 285.5nm

Resonant laser ablation (RLA) is a two-step process, occurring within a pulse of a tunable laser, in which the leading edge of the laser pulse ablates the surface of the solid sample to produce neutral atoms or molecules that are then resonantly ionized by the trailing edge of the same pulse. Resonant laser ablation has been demonstrated to have high sensitivity and provide semi-quantitative results, with very little sample consumption. Resonant laser ablation also provides a simple means for measuring atomic spectra. Characteristics of RLA are potentially useful for studies of toxic and radioactive elements. Resonant laser ablation plays an important role in archeology, environmental sciences, life sciences and other industrial application.In chapter one, the resonant laser ablation technique and it's development are introduced.In chapter two, the basic principle of RLA technique is presented, including the characteristics of laser induced plasma and the principle of resonant laser ionization.In chapter three, the RLA spectra in Ti and Al sample are investigated. The main contents are as followings. (1) Six RLA spectra within the range of 281.5-285.5nm in Ti sample are identified. They are RLA spectra of Fe. (2) The influence of laser energy on RLA spectra isinvestigated. The experimental results show that, as the laser energy increases, the intensity and the width of the RLA spectra line increase. (3) Four RLA spectra of Fe(3d74s(a5F) 3d64s4p(y5G0) )are measured under the same experimental condition. We can conclude from the experimental results that, as the laser wavelength increases, the photo-ionization crosses section of resonant level increase. The result is well fit with the calculation result. (4) The influence of laser energy on RLA signal and non-resonant signal are investigated. It is shown from the experimental results that, as the laser energy increases, the intensity of resonant and non-resonant signal increase respectively. (5) RLA spectra within the range of 281.5-285.5nm in 2#Al and 4#Al sample are measured. The experimental results show that, when the concentration of Fe increases, the intensity of the same RLA spectra line increases. But the spectra line intensity amplitude increased is different from the concentration amplitude increased. The intensity of spectra lines show no similar relation to the concentration of Fe in the samples with different kinds of matrix. So it shows intense influence of the matrix effect on the spectra line intensity.