FREQUENCY STABILIZATION OF DIODE-LASER USING EXTERNAL-CAVITY AND DOPPLER-FREE ATOMIC SPECTRA

We report on the frequency stabilization of a diode laser, in which the long- and short-term stabilities are simultaneously improved. We use an external cavity whose resonance frequency is locked to the center of a Doppler-free spectrum of the Rb-85-D2 line without direct laser frequency modulation. The obtained linewidth of the diode laser is less than 100 kHz and the long-term stability (trackability) estimated from the variation of the error signal is between 2 x 10(-12) and 2 x 10(-14) at the averaging time tau between 100 ms and 100 s. We also propose a conventional method of stabilization of the magnetic field at the Rb cell used for the frequency stabilization.