Laser-Induced Phase Transitions in Vitreous Se Films Obtained by Vacuum-Thermal Evaporation

Femto- and nano-second laser-induced damages in chalcogenide glasses

“…Before the exposure, the spectral shape is typical of that in amorphous Se, with a bump around ∼130 cm −1 and a broad peak at ∼250 cm −1 , which shifts with damage formation to a sharper peak at 237 cm −1 , signifying trigonal Se. 14,26) To the authors' knowledge, this is the first demonstration of photo-crystallization 27) in Se which is induced by pulsed light. No appreciable spectral changes have been produced by the ns pulses.…”

“…[2][3][4][5][6] The results assert that, upon illumination of fs pulses, electronic damage occurs, while thermal effects predominate under ns timescales, reflecting the electron-lattice energy relaxation time of ∼10 ps regions. 7,8) On the other hand, studies on the damage in chalcogenide glasses remain preliminary, [9][10][11][12][13][14][15][16][17] since small bandgap energies of ∼2 eV and lower glass-transition temperatures than ∼600 K infer a priori damageable characters. The small bandgap energy also yields high optical nonlinearity (twophoton absorption coefficient β ∼ 1/E g 3 and nonlinear refractive index n 2 ∼ 1/E g 4 ), 18) which is promising to applications, while it may assist in producing permanent damages through photo-electronic excitations.…”