dc.creator Raab, M. en_US dc.creator Weber, A. en_US dc.date.accessioned 2006-06-15T14:50:39Z dc.date.available 2006-06-15T14:50:39Z dc.date.issued 1983 en_US dc.identifier 1983-TF-01 en_US dc.identifier.uri http://hdl.handle.net/1811/11984 dc.description Author Institution: Molecular Spectroscopy Division, National Bureau of Standards en_US dc.description.abstract Applying heterodyne detection $schemes^{1}$ to laser polarization $spectroscopy^{2}$ increases the sensitivity (S/N ratio) $considerably^{3}$. An acousto-optical modulator (AOM) shifts the pump frequency relative to the probe frequency by the amount of the driving frequency of the AOM thereby avoiding coherent noise due to interference of pump and probe/signal beams. At the same time the pump bean can be amplitude modulated at high frequencies (up to the MHz region) by means of the AOM thereby shifting the detection frequency towards more favorable regions of the laser noise spectrum. Interference of an optimized fraction of the probe bean with the spectroscopic signal generated through the non-linear mixing of the pump and probe beams by the medium finally amplifies the signal at a sensitivity close to the shot noise limit. Examples are given showing spectra of $^{3}\Pi_{u}\leftarrow ^{1}\Sigma_{g}^{+}$ transitions of $Na_{2} (\approx 10^{4}$ times less intense compared to the allowed"" $A^{1}\Sigma_{u}^{+}\leftarrow X^{1}\Sigma_{g}^{+}$ $transition^{4}$) and weak two photon absorption in a Na-heat pipe. Detection of components of the Na-D lines was accomplished in the vapor over the metal at room temperature and with $10^{3}-10^{4}$ atoms in the interaction volume. $^{1}$J. J. Snyder, R. K. Raj, D. Bloch, and M. Ducloy, Opt. Lett. 5. 163 (1980). $^{2}$C. Wieman and T. W. H\""{a}nsch, Phys. Rev. Lett. 36,(1170). $^{3}$M. D. Levenson and G. L. Eesley, Appl. Phys. 19, 1 (1979). $^{4}$J. B. Atkinson, J. Becker, and W. Demtr\""{o}der, Chem. Phys. Lett. 87, 92, 128 (1982). en_US dc.format.extent 122480 bytes dc.format.mimetype image/jpeg dc.language.iso English en_US dc.publisher Ohio State University en_US dc.title HIGH SENSITIVITY HETERODYNE-POLARIZATION SPECTROSCOPY en_US dc.type article en_US
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