Upconversion fluorescence assisted visualization of femtosecond laser filaments in Er-doped chalcohalide 65GeS(2)-25Ga(2)S(3)-10CsCl glass

Blonskyi I., Kadan V., Shpotyuk O., Calvez L., Pavlov I., Pavlova S., ...More

OPTICS AND LASER TECHNOLOGY, vol.119, 2019 (SCI-Expanded) identifier identifier

  • Publication Type: Article / Article
  • Volume: 119
  • Publication Date: 2019
  • Doi Number: 10.1016/j.optlastec.2019.105621
  • Journal Indexes: Science Citation Index Expanded (SCI-EXPANDED), Scopus
  • Keywords: Chalcohalide glass, Femtosecond laser, Filamentation, Upconversion fluorescence, Rare-earth ion, Two-photon absorption, TRANSPARENT MATERIALS, CHALCOGENIDE GLASSES, EMISSION
  • Middle East Technical University Affiliated: Yes


Upconversion fluorescence of Er3+ ions (1 at. %) excited with femtosecond laser pulses of different repetition frequencies (seed laser 76 MHz, and laser amplifier 1 kHz) is studied in the Er-doped chalcohalide glass of 65GeS(2)-25Ga(2)S(3)-10CsCl composition. Strong weakening of fluorescence efficiency at 530 nm and 560 nm and photoinduced darkening are observed under 1 kHz excitation, which is most probably caused by free carriers generated by two-photon absorption. On the other hand, neither weakening nor photodarkening is observed under 76 MHz excitation, this being presumably due to concomitant thermal annealing. Taking an advantage of upconversion fluorescence, the femtosecond filamentation associated with positive changes in refractive index is recorded in the Er-doped 65GeS(2)-25Ga(2)S(3)-10CsCl glass, whereas exceeding the threshold of thermal melting is accompanied by an opposite decrease in the refractive index.