Tunable Solid-State Lasers Based on Rare-Earth-Doped Fluoride Single Crystals

Rare-earth-doped fuorides single crystals have been proven to be reliable and interesting active media for solid-state lasers (SSLs) . In particular, they possess long spectral lifetimes, narrow emission linewidths and the high-quality output beams. These features allow them to compete both with semiconduc- tor laser and solid-state lasers based on other insulating materials and also to achieve laser emission in previously uncovered wavelength regions. In this work I report on the developement of SSLs in the visible, and in the near infrared region around 2 m. Fluoride crystals doped with thulium or co-doped with thulium and holmium can be pumped with laser diode near 800 nm to achieve ecient laser emission in the range 1.8-2.1 m. Thanks to the peculiar absorption properties of wa- ter and atmospheric gases in this region, these sources can be used for laser scalpels, surveillance, long-range LIDARs, and gas detection in the atmosphere. We investigated the spectroscopic, laser properties and tunability of two cu- bic materials, SrF2 doped with thulium (Tm:SrF2) and KY3F10, doped with thulium (Tm:KYF) or co-doped (Tm-Ho:KYF). For the single doped we ob- tained maximum slope eciencies of 67% and 56% respectively, and tunability of 180 nm and 194 nm. In the co-doped sample, we obtained a slope eciency of 24% and a tunability of 61 nm around 2.1 m. In the visible part of the spectrum, compact and reliable laser sources in the deep red region are nowadays required to pump strontium atomic lattice clocks, to reduce the size and complexity of the system for space-oriented applications. We studied the laser capabilities of two dierent hosts: Pr3+:Ba(Y(1x)Lux)2F8 (Pr:BYLF) and Pr3+:LiGdF4 (Pr:GLF). In both we observed tunability around 698 nm clock transition". In Pr:GLF we achieved continuous-wave laser emis- sion at 674, 688, 689, 698, and 707 nm, thus covering all the deep-red wave- lengths required for Sr0 clocks and the clock transition" of Sr+. These results provide the basis for the development of a compact and long-lasting laser plat- form for strontium metrology, based on diode-pumped solid-state lasers. Moreover we demonstrated the potential of praseodymium-doped single- crystal bers (SCFs) as compact and cost-ecient active media for visible lasers, by obtaining for the rst time laser emission in Pr:LiYF4 (Pr:YLF) and Pr:KYF SCFs . These bers were grown using thr relatively new technique of micro- pulling-down, which was proven to be a valid alternative to the 'more traditional' Czochralski method for the growth of monocrystalline laser materials.