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Atomic absorption apparatus using a phase-modulated light beam
 An atomic absorption apparatus using a laser for producing a light beam having a characteristic frequency f, typically ranging from several MHz to several GHz, and a characteristic polarization for measuring the absorption of that light beam by atoms of interest. The apparatus has a modulator to generate a modulating signal to modulate the characteristic frequency f and produce a phase-modulated light beam. The apparatus includes a domain where the specific atoms are located. This domain is positioned in the path of the phase-modulated light beam such that the phase-modulated light beam encounters the specific atoms when passing through the domain and some of the specific atoms absorb a portion of the phase-modulated light beam. Typically, the domains containing the atoms of interest include process chambers for vacuum coating, ion milling, sputtering, mass spectroscopy vapor coating or deposition, and the like. The amount of light absorbed depends on the motion of the atoms relative to the phase-modulated light beam. 
Board of Trustees of the Leland Stanford Junior University
G G
G01N G01J
inventional inventional
Robert H. Martin M. Malcolm R. Weizhi Charles H. Steven J.
Hammond Fejer Beasley Wang Ahn Benerofe