Indirect Amplitude Stabilization of a Tunable Laser through Control of the Intensity of a Pump Laser by an Electro-Optic Modulator

Abstract

A novel method has been developed to stabilize the intensity of a tunable laser. In this method, the tunable laser is amplitude-stabilized indirectly by controlling the intensity of the pump laser through an electro-optic modulator placed between the pump and the tunable lasers. A small portion of the tunable laser beam was split into a reference photodiode to provide a reference signal for the feedback driver to drive the Pockels cell. Any fluctuation in the intensity of the tunable laser is compensated for by varying the intensity of the pump laser through the feedback driven Pockels cell. Results obtained on the Ti-sapphire laser pumped by an ion laser demonstrate that up to 100 × reduction in the laser noise level can be accomplished by use of this method. Furthermore, with this method, it is possible to adjust the intensity of the laser to be exactly equal for different wavelengths, and to maintain this level for as long as the stabilization is activated. Applications of this method for different types of tunable lasers, including dye and F-center lasers, are discussed.