[Frequency stabilization of diode laser using zeeman spectra].
Zeeman split takes place for the hyperfine level structure of neutral atoms where magnetic field exists. In addition, being excited by right circularly polarized light and left circularly polarized light, atoms obey different transition rules. So, the absorption peak between the hyperfine Zeeman level shifts with respect to the absorption peak without magnetic field. Accordingly, the authors demonstrated a kind of simple and flexible method to stabilize the frequency of diode laser. The linewidth of diode laser was reduced to less than 1 MHz using this method. Through analyzing the experiment results, the authors found that when the sum of both shifts of the hyperfine level of atoms excited by right circularly polarized light and left circularly polarized light was equal to the FWHM (Full Width at Half Maximum) of the saturated absorption peak, the laser frequency was stabilized best.