Troisième Symposium sur les Etalons de Fréquence et la Métrologie / Third Symposium on Frequency Standards and Metrology

J. Phys. Colloques 42 (1981) C8-59-C8-71
DOI: 10.1051/jphyscol:1981808

PROGRESS TOWARD PHASE-STABLE OPTICAL FREQUENCY STANDARDS

J.L. Hall¹, L. Hollberg², Ma Long-sheng³, T. Baer⁴ et H.G. Robinson<sup>5

1</sup>  Staff Member, Quantum Physics Division, National Bureau of Standards.
²  Joint Institute for Laboratory Astrophysics, National Bureau of Standards and University of Colorado, Boulder, Colorado 80309, U. S. A.
³  East China Normal University, Shanghai
⁴  Spectra Physics, Mountain View, California
⁵  1980-81 JILA Visiting Fellow, on leave from Department of Physics, Duke University, Durham, North Carolina.

Abstract
The sensitivity of laser spectroscopy is usually limited by laser amplitude noise of a technical nature. We describe a new and very sensitive detection technique which basically eliminates this source of noise by encoding the resonance information into RF frequencies using FM modulation followed by optical heterodyne and RF phase-sensitive detection. The method is applied to laser stabilization and sub-Doppler spectroscopy. Calculation shows the method provides an available sensitivity within 3.4 dB of the theoretical limit for ideal absorption spectroscopy.