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LOLS research in technology for the development and application of new fiber-based sensors.

Coelho J, Nespereira M, Silva C, Rebordão J - Sensors (Basel) (2012)

Bottom Line: This paper presents the research made at the Laboratory of Optics, Lasers and Systems (LOLS) of the Faculty of Sciences of University of Lisbon, Portugal, in the field of fiber-based sensors.Three areas are considered: sensor encapsulation for natural aqueous environments, refractive index modulation and laser micropatterning.We present the main conclusions on the issues and parameters to take in consideration for the encapsulation process and results of its design and application.

View Article: PubMed Central - PubMed

Affiliation: Department of Physics, Faculty of Sciences, University of Lisbon, Lisboa, Portugal. joao.coelho@fc.ul.pt

ABSTRACT
This paper presents the research made at the Laboratory of Optics, Lasers and Systems (LOLS) of the Faculty of Sciences of University of Lisbon, Portugal, in the field of fiber-based sensors. Three areas are considered: sensor encapsulation for natural aqueous environments, refractive index modulation and laser micropatterning. We present the main conclusions on the issues and parameters to take in consideration for the encapsulation process and results of its design and application. Mid-infrared laser radiation was applied to produce long period fiber gratings and nanosecond pulses of near-infrared Q-switch laser were used for micropatterning.

No MeSH data available.


Related in: MedlinePlus

FEM simulation of (a) temperature and (b) von Mises stress distribution (color scale) for a 1 s irradiation of a 125 μm diameter silica fiber by a 35 mW CO2 laser beam. The beam is considered has having a spot size coincident with the fiber’s diameter.
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f9-sensors-12-02654: FEM simulation of (a) temperature and (b) von Mises stress distribution (color scale) for a 1 s irradiation of a 125 μm diameter silica fiber by a 35 mW CO2 laser beam. The beam is considered has having a spot size coincident with the fiber’s diameter.

Mentions: An example of a FEM analysis is presented in Figure 9. This simulation was made with COMSOL multiphysics™ and considered a 35 mW irradiation for 1 s. The fiber was simulated by a cylinder of silica (103 cm−1 absorption coefficient at 10.6 μm wavelength); the cylinder has a diameter of 125 μm and a length (just for simulation purposes) of 3 mm. The ambient temperature is considered to be 295 K. The 3D mesh was divided in three volumes in order to allow a tighter mesh size in the central part of the fiber (where the laser beam incidence is simulated) without increasing the computational load. In the central part of the fiber, the mesh was defined by 12,411 tetrahedral elements (0.0439 element volume ratio). The initial condition, at t = 0 s, is that the temperature of the piece is uniform and equal to the ambient temperature (295 K). The analysis includes thermo-mechanical modeling which not only allows studying the temperatures distribution in the silica fiber due to laser irradiation but also the stresses generated within the bulk material. Up to the moment, the existence of the pre-strain and the inner strain of the fiber due to the selective doping solely in the core region were not implemented in the model. This will be made in future developments.


LOLS research in technology for the development and application of new fiber-based sensors.

Coelho J, Nespereira M, Silva C, Rebordão J - Sensors (Basel) (2012)

FEM simulation of (a) temperature and (b) von Mises stress distribution (color scale) for a 1 s irradiation of a 125 μm diameter silica fiber by a 35 mW CO2 laser beam. The beam is considered has having a spot size coincident with the fiber’s diameter.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3376623&req=5

f9-sensors-12-02654: FEM simulation of (a) temperature and (b) von Mises stress distribution (color scale) for a 1 s irradiation of a 125 μm diameter silica fiber by a 35 mW CO2 laser beam. The beam is considered has having a spot size coincident with the fiber’s diameter.
Mentions: An example of a FEM analysis is presented in Figure 9. This simulation was made with COMSOL multiphysics™ and considered a 35 mW irradiation for 1 s. The fiber was simulated by a cylinder of silica (103 cm−1 absorption coefficient at 10.6 μm wavelength); the cylinder has a diameter of 125 μm and a length (just for simulation purposes) of 3 mm. The ambient temperature is considered to be 295 K. The 3D mesh was divided in three volumes in order to allow a tighter mesh size in the central part of the fiber (where the laser beam incidence is simulated) without increasing the computational load. In the central part of the fiber, the mesh was defined by 12,411 tetrahedral elements (0.0439 element volume ratio). The initial condition, at t = 0 s, is that the temperature of the piece is uniform and equal to the ambient temperature (295 K). The analysis includes thermo-mechanical modeling which not only allows studying the temperatures distribution in the silica fiber due to laser irradiation but also the stresses generated within the bulk material. Up to the moment, the existence of the pre-strain and the inner strain of the fiber due to the selective doping solely in the core region were not implemented in the model. This will be made in future developments.

Bottom Line: This paper presents the research made at the Laboratory of Optics, Lasers and Systems (LOLS) of the Faculty of Sciences of University of Lisbon, Portugal, in the field of fiber-based sensors.Three areas are considered: sensor encapsulation for natural aqueous environments, refractive index modulation and laser micropatterning.We present the main conclusions on the issues and parameters to take in consideration for the encapsulation process and results of its design and application.

View Article: PubMed Central - PubMed

Affiliation: Department of Physics, Faculty of Sciences, University of Lisbon, Lisboa, Portugal. joao.coelho@fc.ul.pt

ABSTRACT
This paper presents the research made at the Laboratory of Optics, Lasers and Systems (LOLS) of the Faculty of Sciences of University of Lisbon, Portugal, in the field of fiber-based sensors. Three areas are considered: sensor encapsulation for natural aqueous environments, refractive index modulation and laser micropatterning. We present the main conclusions on the issues and parameters to take in consideration for the encapsulation process and results of its design and application. Mid-infrared laser radiation was applied to produce long period fiber gratings and nanosecond pulses of near-infrared Q-switch laser were used for micropatterning.

No MeSH data available.


Related in: MedlinePlus