| Popis: |
A visible chemical laser on the BiF(A-X) transistions at 430-470 nm can potentially be generated by the interaction of Bi-atoms with metastable species such as NF(a1Δ). Experiments were performed in which these constituents were obtained in situ by fast pulsed CO2 laser pyrolysis of FN3 and Bi(CH3)3, respectively. Time-resolved optical diagnostics were used to follow the concentrations of FN3, NF(a1Δ), Bi(CH3)x, Bi(2D) and BiF(A). The optimal concentrations of FN3 and Bi(CH3)3 were limited by NF(a1Δ) self-annihilation and Bi(2D) quenching reactions, respectively. The Bi(CH3)3 was found to be only 20 % dissociated at the peak of the NF(a1Δ) time profile and the yield of Bi-atoms from dissociated Bi(CH3)3 was determined to be approximately 5%; however, significant recycling of the active Bi/BiF species was observed at a limiting rate of 4 - 5 x 10-11 cm3/s, driven by NA(a1Δ). On the basis of these results, a peak BiF(A) concentration of 1013/cm3 was predicted by kinetic modeling and subsequently observed. The model also predicts an absolute population inversion of the BiF(A-X) transistion at high NF(a1Δ) concentration with unsaturated gains of approximately 10-3/cm. Intracavity experiments have verified that the BiF(X) ground state concentration is low enough relative to the excited state to generate at least a partial inversion, and initial evidence for an absolute population inversion has been obtained.© (1990) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only. |
