When the probe spectral range needs to be extended farther into the blue, the continuum has to be generated in CaF
2. This allows for probing the transients down to at least 350 nm. Due to a higher continuum generation threshold in CaF
2 and a lower thermal conductivity compared to sapphire, it is necessary to periodically move the substrate while generating continuum.
The UV-Continuum is a CaF2 based continuum generation module for Helios with the spectral range of 350 nm - 750 nm. It includes a mounted high quality CaF2 crystal and a computer controlled motorized translation stage for moving the crystal and providing a stable high quality continuum. The stage module controls are integrated into the Helios data acquisition software.
