Visible waveguide laser in fluoride crystals

Today, lasers play a key role in many aspects of our society, from everyday life to scientific research. Some of these applications require a laser with wavelength in the visible range, from 400 to 750nm, and praseodymium ions are an interesting source for visible laser realization, possessing emission lines from 480nm to 720nm. Moreover, if embedded in fluorides, it possesses all the lines needed by strontium-based atomic clocks and does not have all the disadvantages of laser diodes today employed like encumbrance and frequency runaway. In particular, LiLuF4 showed better thermomechanical properties with respect to the more common LiYF4. A miniaturized source can be obtained by writing waveguides with femtosecond-long laser pulses. For the project of this thesis, femtosecond-written waveguides have been realized on Pr:LiLuF4. The writing procedure has been carried out by ALF group of University of Salamanca, which collaborate with us on this project. Waveguides have been characterized by transmission measurement, observing transmission losses of 0.12dB/cm, a value lower than all previously measured in waveguides written in fluorides. A waveguide laser has been obtained, for the first time in this material, which operation wavelengths are 604nm and 721nm. Moreover, laser operation at 698nm has been realized for the first time in a praseodymium-based waveguide laser