Alkali halide crystals containing color centers (CCs) are well known as laser active media in optically pumped tunable solid state lasers generally operating at liquid nitrogen temperature. Among them

lithium fluoride has several unique characteristics because it can hold laser active defects stable at room temperature (RT) and emit in the visible and near infrared. Despite the deep knowledge on alkali halide crystals

little attention was devoted to non epitaxial alkali halide films. In the last years we devoted our attention to the growth and characterization of LiF films in order to study the spectroscopic properties of CCs created by low energy electron beams for application in integrated active devices. Polycrystalline LiF thin films of total thickness t between 0.5 and 3.8μm were grown by thermal evaporation on amorphous substrates

mantained at fixed temperature

T

s

between 30 and 350℃ during deposition. Their structural

morphological and optical properties are strongly dependent on the evaporation parameters

especially on

T

s

. Low energy electron beam irradiation gives rise to the efficient formation of stable F

2

and F

3

+

centers. Properties of photoluminescence at room temperature were studied. It shows that active channels (F

2

and F

3

+

centers) with sizeable optical gain and a substantial increase of the refractive index are promising for the realization of active optical waveguide devices which are tunable in the visible.