ABSTRACT
Lanthanide series solid state lasers which operate in the near to mid infrared region of the spectrum are explored in this chapter. Lanthanide series lasers which produce wavelengths longer than ∼1.4 µm are analyzed here, in particular, lasers having lanthanide series atoms of Dy, Ho, Er and Tm. Lasers producing wavelengths longer than 1.4 µm enjoy an advantage with regard to eye safety because these wavelengths are absorbed volumetrically in the vitreous humour of the eye. Therefore, the laser radiation is not focused onto the retina of the eye, which greatly increases the radiation level required for eye damage. These active atoms also often have other common properties including a dependence on energy transfer processes. Specifically the population of various manifolds or groups of closely spaced energy levels are populated through the transfer of quanta of energy from other manifolds. Energy transfer processes will also be covered in this chapter. Not covered here are lanthanide series lasers in glasses or fibre lasers (see chapter B4), including lasers utilized for communication purposes.
