Cr:LiSrAlF6 optical waveguides defined by ion beam implantation

Planar optical waveguides have been fabricated in the laser material Cr: LiSrAlF6 using ion implantation. The 2 MeV He+ implant forms a low refractive index optical barrier at the end of the ion range, with an index decrease of similar to 2.5% for a dose of 2 x 10(16) ions/cm(2) at 77 K. The index at the surface (electronic stopping region) is slightly increased by similar to 0.15%. Post-implant thermal, and pulsed laser surface annealing have been carried out and compared. It is shown how pulsed laser annealing can remove scattering features from the waveguide surface. Waveguide losses have been measured at 488 and 633 nm by end-fire coupling, and are in the region of a few dB/cm. The waveguide absorption spectrum measured by white light end-coupling has been determined, and suggests that the charge state of the Cr3+ remains predominantly unchanged. The study shows that ion implantation is a possible way for making Cr: LiSrAlF6 waveguide lasers.