High-efficiency laser-pumping system for magnetic resonance imaging

Marziale Milani; Guido Baroni; Lorenzo Ferraro; P. Sozzani; Massimo Adobati; S. Ravetta

doi:10.1117/12.384902

3 May 2000 High-efficiency laser-pumping system for magnetic resonance imaging

Marziale Milani, Guido Baroni, Lorenzo Ferraro, P. Sozzani, Massimo Adobati, S. Ravetta

Proceedings Volume 3911, Biomedical Diagnostic, Guidance, and Surgical-Assist Systems II; (2000) https://doi.org/10.1117/12.384902
Event: BiOS 2000 The International Symposium on Biomedical Optics, 2000, San Jose, CA, United States

Abstract

Recently the demand for hyperpolarized noble gases is arising to improve NMR spectroscopy resolution for imaging. Hyperpolarization of noble gases is achieved by spin- exchange with alkali metal. atoms that undergo optical pumping by circularly polarized radiation. Optical pumping is usually achieved by high power semiconductor lasers. These sources have a bandwidth very large when compared with the transition bandwidth of the optically active species. This has two serious consequences: (i) the request of high power lasers, (ii) the losses that the unemployed energy delivered to the Rb vapor can provide in the efficiency of the energy transfer. Object of our investigation will be the comparison of two experimental set ups for optical pumping of Rb vapor where pumping is given in one case by a dye laser pumped by a UV nitrogen laser built in our laboratory according to the Blumlein scheme and in the other case by a semiconductor laser. Major elements that will be discussed are (1) the role of stimulated emission of Rb vapor to increase the pumping efficiency, (2) the fate of resonant photons that are emitted during Rb decays, (3) the role of applied magnetic fields in the efficiency of pumping processes.

Citation Download Citation

Marziale Milani, Guido Baroni, Lorenzo Ferraro, P. Sozzani, Massimo Adobati, and S. Ravetta "High-efficiency laser-pumping system for magnetic resonance imaging", Proc. SPIE 3911, Biomedical Diagnostic, Guidance, and Surgical-Assist Systems II, (3 May 2000); https://doi.org/10.1117/12.384902

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