Abstract

Diode-pumped solid-sate laser systems combined with CPA technique are promising devices for generation of highest peak intensities. With regard to the choice of a suitable gain medium its spectroscopic properties determine the scaling of a laser system towards both highest output pulse energy and shortest pulse duration. In order to saturate the absorption with a minimum number of diode lasers a long fluorescence lifetime of the gain medium is desired. Ytterbium-doped fluorides such as Yb:CaF₂ and Yb:SrF₂ comprise a broad emission spectrum and a comparable long fluorescence lifetime. At a dopant concentration of 3.3% (atm.) we measured a radiation lifetime of 2.2 ms for Yb:CaF₂ and 4.6 ms for Yb:SrF₂. Fig. 1 (left) shows absorption and emission cross section whereas the latter is determined by reciprocity method. According to ISO 11254-1 standard the damage threshold of Yb:CaF₂ was measured to be 53 J cm⁻² at a pulse duration of 10 ns (FWHM) and a center wavelength of 1064 nm.

© 2007 IEEE