Fast wavelength-switching of a diode-pumped solid-state disk laser

The functionality of two experimental setups for fast wavelength-switching of an Yb:YAG disk laser is tested and characterized. The first setup consists of two resonators sharing one disk. Both resonators are alternately opened by a chopper disk. Each resonator is tuned independently by a set of a two-stage Lyot filter and an etalon. Up to 1500 Hz the setup can switch between two freely selectable wavelengths (linewidth (fwhm) << 1 pm) within the complete Yb:YAG tuning range (from 1020 nm to 1055 nm) emitting a maximum average power of 105 mW. The power of both resonators differs by a factor of 0.7. Their pointing stability amounts to 20 mu rad. The second setup consists of a single tunable resonator (two-stage Lyot filter, etalon) additionally equipped with an electro-optical device (Faraday rotator or Pockels cell) providing a high pointing stability of better than 1 mu rad. The wavelength switches occur stepwise and are predetermined by the etalon (about 90 pm or multiples thereof). The Faraday rotator suffers from its high thermal load and operates for some few 10 s only at 0.5 Hz. The resonator with the Pockels cell provides long term stability at 1000 Hz, switching steps up to 1.1 nm and a power ratio of 0.83 for the selected wavelengths.