Scale offset for frequency tracker

A new method for wide frequency laser control is presented. A laser with P and S polarizations and an ultra-stable ULE made Fabry-Pérot interferometer (FP) are used to lock alternatively a laser frequency from one FP signal to the other by the mean of two acousto-optic modulators (AOM). The stability of the FP is by this way transferred to the laser. The servo-locking system overcome the free spectral range limit by switching from one Airy function to the second one. As the method covers as many free spectral range as desired, the laser frequency can be driven all over the laser gain curve. Experimental setup and resolutions expected of the instrument are discussed