Title

Laser diode and optical parametric oscillator laser applications in laser ablation and multielement laser excited atomic fluorescence spectrometry

Date of Completion

January 1997

Keywords

Chemistry, Analytical|Physics, Optics

Degree

Ph.D.

Abstract

A pulsed (10 Hz) optical parametric oscillator (OPO) laser system based on $\beta$-barium borate (BBO) was characterized for use in analytical atomic spectrometry. The laser was used as the excitation source for flame and graphite furnace Laser Excited Atomic Fluorescence Spectrometry (LEAFS). Rapid, sequential, multielement analysis with the OPO LEAFS was demonstrated by slew scan of the laser. Good accuracy and precision were achieved by use of flame and graphite furnace OPO LEAFS for real sample analyses. Comparable or improved LEAFS detection limits over literature values were obtained. The high sensitivity of LEAFS allowed sufficient initial dilution to remove interferences that were encountered in the real sample analyses.^ The potential of a 930 nm, 50 W continuous wave diode laser array for solid sample vaporization was investigated. It was found that the power density of the focused laser output was not sufficient for ablation of metals, but vaporization of dry bovine liver powder was feasible. Determination of lead in bovine liver (SRM1577a) was performed accurately with a diode laser vaporization instrument.^ A computer-controlled 2048-pixel linear CCD array detection system was developed for spectroscopy applications. The CCD was characterized for charge transfer efficiency (CTE) and wavelength response range. Successful applications were shown for spatial and spectral detection in conjunction with the solid state laser and diode laser projects described above. ^