Optical waveguides in LiF by ion-beam irradiation: fabrication and characterisation

In our experiments, we have successfully managed to produce optical waveguides in polished LiF crystals by using He/sup +/ ion beam irradiation. The beam was masked by a metal window, producing large irradiated stripes about 1 mm wide. Irradiation energy was chosen to be 1.1 MeV, since it allowed to produce 3 /spl mu/m thick waveguides with a parabolic colour centre creation and thus refractive index profile, which was very suitable for characterisation purposes.