Annealing behaviour of natural topaz implanted with W and Cr ions

Single crystalline samples cleaved from natural topaz were implanted with W and Cr ions with fluences in the range 5 x 10(15)-3 x 10(17) ions/cm(2). A fter implantation the implanted region becomes amorphous in all the samples and the absorption spectra reveal significant changes in the near infrared region in the wavelength range 2000-3000 nm. For the lowest doses the tran smission has a maximum in this wavelength region. The stoichiometry of the implanted surface changes due to the loss of fluorine after annealing at 60 0 degrees C. This loss is not observed in virgin samples. Chromium starts t o diffuse into the bulk after annealing at 600 degrees C while W profile re mains stable up to 800 degrees C, After annealing at 800 degrees C the opti cal absorption shows a reduction while the damage profile remains without a ny noticeable change. (C) 2000 Elsevier Science B.V. All rights reserved.