Abstract: A dye laser is stabilized for operation at a narrow line width by a control system which utilizes two reference interferometers.One reference interferometer has a small free spectral range for stabilizing the frequency of operation of the dye laser at the relatively narrow line width, and the other reference interferometer has a free spectral range substantially larger than the first reference interferometer.The dye laser is servo locked to a side of a transmission fringe of the first reference interferometer to maintain operation at a selected frequency with the narrow line width in the absence perturbations that can cause a mode hop.When a perturbation does cause a mode hop, the second reference interferometer detects the extent and the direction of the mode hop. It then automatically stops the scanning system of the dye laser, resets the servo back to the selected frequency and restarts the scanning system of the dye laser in operation at the selected frequency, all within a short period of time.