We report on a method of laser stabilization, Doppler-free bichromatic lock (DFBL) in which we use the differential signal of two Lamb-dips shifted in frequency by means of an AOM. We show that this method provides us with a tool for precision locking to a molecular or atomic transition and is relatively simple to implement in a diode or dye laser system without the use of a frequency modulation of the laser or lock-in amplifier. A simple model description of this method is presented and the experimental realization is shown for a dye laser at the Na D
1 and D
2 line.
PACS 42.79.Jq; 42.60.Lh; 42.62.Fi