Confocal and Atomic Force Microscopies of Color Centers Produced by Ultrashort Laser Irradiation in LiF Crystals

Abstract

We report properties of the spatial and spectral distribution of color centers produced in LiF single crystals by ultrashort high intensity laser pulses (60 fs, 10 GW) using confocal spectral microscopy and atomic force microscopy. We could identify a large amount of F centers that gave rise to aggregates such as F2, F4, F2+ and F3+ distributed in cracked shape brownish areas. We have taken a 3D image using confocal microscopy of the sample (luminescent image) and no difference is observed in the different planes. The atomic force microscopy image clearly shows the presence of defects on the modified surface. The formation of micrometer or sub‐micrometer voids, filaments and void strings was observed and related to filamentation process.