IODINE HYPERFINE STRUCTURE OBSERVED IN SATURATED ABSORPTION AT 633-NM

Hyperfine components of the R(127) line of the 11-5 band of molecular iodine at 633 nm have been observed by saturating the absorption inside the cavity of a single-frequency HeSingle Bond signNe laser. The component widths of 4.5 MHz were broadened a factor of 2 by 1-Torr iodine pressure, or by 500-G magnetic field. Since no wavelength shift as large as 2 MHz was observed, wavelength perturbations from these sources should be controllable to less than 2 × 10-13λ. The use of one of these components as a reference for laser stabilization is suggested. © 1969 The American Institute of Physics.