It was shown that exposure of soda-lime glass to ultra-fast laser pulses at 800nm caused coloration (darkening). This coloring with time-resolved measurements of the transmission of 633nm light through the glass during laser exposure was characterized. Reverse processes (partial bleaching) operate on time scales from µs to seconds. The competition between coloration after the femtosecond pulse and the subsequent transmission recovery limits the darkening that could be achieved at a given femtosecond pulse energy and repetition rate. The response of soda-lime glass to 400 and 267nm ultra-fast pulses was quite similar, although much lower pulse energies were required for darkening. It was argued that darkening was due to absorption processes that produced mobile charge carriers, which then interacted to produce trapped hole centers (H3+) that absorb strongly at 633nm. Trapped electrons (that formed E centers) were the likely cause of the accompanying loss of transmission in the near ultraviolet. Finally, it was shown that diffraction gratings could be rapidly and easily produced in this material by using holographic methods.

Color Center Formation in Soda-Lime Glass with Femtosecond Laser Pulses. J.B.Lonzaga, S.M.Avanesyan, S.C.Langford, J.T.Dickinson: Journal of Applied Physics, 2003, 94[7], 4332-40