Raman spectroscopy of femtosecond laser written low propagation loss optical waveguides in Schott N-SF8 glass

Abstract

We have performed high repetition rate femtosecond laser bulk modification of TiO2-SiO2 based glass (Schott N-SF8 glass), leading to a decrease in the refractive index near the focal volume. From Raman and X-ray microanalysis we have associated the decrease in the refractive index to a volume expansion due to glass network modifications induced by the laser irradiation. By writing two lines close together we have been able to confine the optical mode and obtain propagation losses of 0.7 dB/cm in the near infrared.

Effect of Silver Nanoparticles on the Optical Properties of Double Line Waveguides Written by fs Laser in Nd3+-Doped GeO2-PbO Glasses

“…The peaks at 782.3 cm −1 and at 867.4 cm −1 (bulk) corresponded to Ge-O − and Ge-O-Ge symmetric stretching vibrations in the GeO 4 tetrahedral units [ 6 , 30 ] and asymmetric stretching vibrations of Ge-O-Ge bonds, respectively; a slight change of these peaks was noticed in the laser focal region, indicating little influence of the laser irradiation process too. It is important to highlight that a Raman shift due to laser-induced modification of the structure was also reported for other glass [ 31 , 32 ].…”

High-Density Well-Aligned Single-Walled Carbon Nanotubes for Application as a Saturable Absorber with a High-Pass Filter Effect in an Erbium-Doped Ultra-Short-Pulse Fiber Laser

“…Ultra-short-pulse fiber lasers are currently a widespread platform for a large number of high-tech areas of production and medicine. − Their key advantages, such as robustness, relative cost, and high stability of output characteristics, have led to a rapid interest in various scientific and research fields. Since the first experimental demonstration of an all-fiber passive mode-locked (ML) laser, the performance of such lasers has significantly improved due to which such systems have become the standard of master oscillators.…”