Bragg gratings were fabricated in an Sn-Er-Ge-codoped silica fiber with a phase mask and ultraviolet radiation from a 248-nm KrF excimer laser. The photosensitivity of the fiber was examined by studying the initial growth rate of the gratings written into it. The thermal stability of the gratings was investigated and modeled in terms of both the refractive-index modulation and the effective refractive index of the fiber core. It was shown that the temperature-induced irreversible shift in the Bragg wavelength could not be predicted by the isothermal decay of the refractive-index modulation. Finally, the potential of the gratings written into the fiber is discussed in terms of their use in high-temperature-sensing applications.
Download full-text PDF |
Source |
|---|---|
| http://dx.doi.org/10.1364/josaa.21.001503 | DOI Listing |
Publication Analysis
Top Keywords
Similar Publications
We report a strength-enhanced waveguide second-order line-Bragg grating (WLBG) directly written with femtosecond laser in bulk glass by using "offset" to exploit the slow-light effect. This design eschews the use of multiple waveguides and/or waveguide bundles for light guiding. Instead, it only employs a single-laser-pass waveguide (SLPWG) with a refractive index change of 1.
View Article and Find Full Text PDFWe present what we believe to be a novel optical fibre device for real-time measurements of near-infrared chromatic dispersion of a liquid medium from 1100 nm to 1700 nm. This inline optical fibre chromatic dispersion analyser is based upon collocated fibre long-period gratings written adjacently in the core by femtosecond laser inscription yielding 8 attenuation bands associated with different cladding modes, yielding 8 independent measurements. This fibre device is tested on a series of chemical compounds associated with wines.
View Article and Find Full Text PDFAlterations in center-surround contrast suppression in patients with major depressive disorder.
Sci Rep
November 2024
Department of Psychiatry and Psychotherapy, Medical Center - University of Freiburg, Faculty of Medicine, University of Freiburg, Freiburg, Germany.
Article Synopsis
- Previous electroretinogram studies show that people with major depressive disorder (MDD) have reduced retinal contrast gain, affecting their visual perception.
- The study compares contrast suppression in 21 MDD patients and 23 healthy controls (HC) using various stimuli and finds that MDD patients demonstrate less contrast suppression, especially with high stimulus contrast.
- These findings suggest that altered dopamine function and changes in retinal processing may contribute to the visual perception issues observed in individuals with MDD.
High Refractive Index, Low Birefringence Holographic Materials via the Homopolymerization of 1,2-Dithiolanes.
ACS Appl Mater Interfaces
August 2024
Materials Science and Engineering Program, University of Colorado Boulder, Boulder, Colorado 80309, United States.
High refractive index, low birefringence photopolymers were created via the radical-mediated, ring opening homopolymerization of 1,2-dithiolane functionalized monomers and were subsequently evaluated as holographic recording media. This investigation systematically characterized the reaction kinetics, thermodynamics, and volume shrinkage of the 1,2-dithiolane homopolymerization as well as the optical transparency, refractive index, birefringence, and holographic performance of multifunctional 1,2-dithiolane functionalized monomers and their resultant polymers. Real-time kinetic and thermodynamic analyses of a monofunctional 1,2-dithiolane monomer, lipoic acid methyl ester (LipOMe), indicated rapid monomer conversion, exceeding 90% in 60 s, with an overall enthalpy of reaction of 18 ± 1 kJ/mol.
View Article and Find Full Text PDFA silica volume Bragg grating (VBG) is used to filter the light of a mid-infrared (mid-IR) supercontinuum laser. The VBG with a 7 µm period was inscribed with 800 nm pulses with a 100 fs duration and the phase-mask technique over a glass thickness of 3 mm. Despite silica's absorption, the VBG allows obtaining a narrowband light source tunable from 2.
View Article and Find Full Text PDFWant AI Summaries of new PubMed Abstracts delivered to your In-box?
Enter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!