Photothermal-induced frequency stabilization of a solid-state monolithic Nd:YVO₄ laser

We report on a novel frequency stabilization method of a monolithic solid-state microchip laser. Here, a Nd:YVO₄/YVO₄ laser was constructed with an additional erbium and ytterbium co-doped phosphate glass (Er:Glass) incorporated into the resonator. By illuminating the Er:Glass with an intensity modulated auxiliary 1.55 µm beam controlled photothermal-induced optical path-length changes of the resonator were observed, and utilized for frequency stabilization of the main emission of the solid-state 1064 nm laser. Error signal was obtained from beating the emission with an identical, passively stabilized laser. The presented laser stabilization technique provides a relative frequency stability at the level of 4.5  ×  10⁻¹²@10s, without affetcing the output power of the 1064 nm laser. (letter)