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Published on: November 22, 2019
Refractive index modification using fs-laser double pulses
Optics Express
|June 24, 2009
Summary
Femtosecond laser double pulses create buried waveguides in glass by altering the refractive index. Optimal time delays between pulses significantly enhance this refractive index change, up to 2x10(-3) in fused silica.
Area of Science:
- Materials Science
- Optics and Photonics
- Laser Physics
Background:
- Fabrication of optical waveguides is crucial for integrated photonics.
- Femtosecond laser processing offers precise material modification capabilities.
- Understanding laser-matter interactions is key to optimizing waveguide properties.
Purpose of the Study:
- To investigate the manufacturing of buried waveguides in glass using femtosecond laser double pulses.
- To determine the impact of pulse delay on refractive index change (Deltan).
- To explore the underlying physical mechanisms responsible for refractive index modification.
Main Methods:
- Irradiation of glass samples with femtosecond laser double pulses.
- Measurement of waveguide numerical aperture (NA) to quantify refractive index change.
- Characterization using light microscopy.
Main Results:
- Refractive index change (Deltan) is highly dependent on the time delay (Deltat) between laser pulses.
- A maximum Deltan of up to 2x10(-3) was achieved in fused silica.
- Optimal Deltan was observed for Deltat values between 400 and 800 ps.
Conclusions:
- Femtosecond laser double pulses provide an effective method for creating buried waveguides with significant refractive index modification.
- The observed refractive index changes are influenced by thermal effects and the formation of self-trapped excitons and color centers.
- Further research into pulse delay optimization can lead to improved waveguide fabrication.
