High-resolution Fourier spectroscopy as a tool for studying quality of rare-earth-doped crystals

Three examples were considered of the use of high resolution Fourier-transform optical spectroscopy for studying quality of rare-earth-doped crystals. The first example was connected with defects present in crystals grown by flux techniques. The second example dealt with detection of stresses and deformations in rare-earth-containing crystals, by registering splitting of spectral lines. The third example showed that a very small amount （at the level ofppm） of different RE ions present in a crystal could be determined using high-resolution spectroscopy. This work was carried out by the author＇s group in collaboration with several institutions in Rus- sia and abroad.