CW Yb:YSO diode pumped laser emitting at 1003.4 nm for the development of a stable frequency standard

Diode pumped solid-state lasers realizes ultra-stable optical sources for spectroscopy or gravitational wave detection. A laser emitting at 501.7 nm can be stabilized on Iodine transition in order to have an ultra-stable standard of optical frequencies, as this wavelength corresponds to the narrowest transition line in the visible (only a few kHz) for I₂. This wavelength could be reached by frequency doubling a laser source emitting at 1003.4 nm. Ytterbium-doped materials are good candidates for this kind of source around 1 μm. Among numerous selected crystals, Yb:YSO has high stimulated emission cross-section at 1003.4 nm. Developing an ytterbium laser operating at 1003.4 nm is a challenge since the lower level of the laser transition is strongly populated. So, we need a high and homogeneous pump power density all along the crystal in order to reach a sufficient gain at 1003.4 nm.