Paper
14 May 2008 Designing laser-induced refractive index changes in "thermal" glasses
R. Stoian, A. Mermillod-Blondin, C. Mauclair, N. Huot, E. Audouard, I. M. Burakov, N. M. Bulgakova, Y. P. Meschcheryakov, A. Rosenfeld, A. Husakou, I. V. Hertel
Author Affiliations +
Abstract
Ultrafast lasers emerged as promising tools to process refractive index changes in band-gap materials, resulting in waveguiding functions. Positive refractive index changes were often reported in fused silica matrices. However, in glasses characterized by slow electronic relaxation and high thermal expansion, the refractive index change is usually negative, detrimental for waveguide writing. This relates to the formation of hot regions, where, due to thermal expansion, material is quenched in low-density phases. We discuss control mechanisms related to spatio-temporal heat-source design which may be tuned by temporally shaped laser radiation. Programmable temporal tailoring of pulse envelopes triggers transitions from thermal expansion to directional inelastic flow. Consequently, material compaction leads to a positive refractive index change and guiding structures may thus be created. From an application perspective, the structuring quality degrades with the focusing depth due to wavefront distortions generated at the air-dielectric interface inducing spatial energy dispersion. Spatial beam tailoring corrects beam propagation distortion, improving the structuring accuracy. The corrective process is becoming important when laser energy has to be transported without losses at arbitrary depths, with the purpose of triggering mechanisms of positive index change.
© (2008) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
R. Stoian, A. Mermillod-Blondin, C. Mauclair, N. Huot, E. Audouard, I. M. Burakov, N. M. Bulgakova, Y. P. Meschcheryakov, A. Rosenfeld, A. Husakou, and I. V. Hertel "Designing laser-induced refractive index changes in "thermal" glasses", Proc. SPIE 7005, High-Power Laser Ablation VII, 700518 (14 May 2008); https://doi.org/10.1117/12.783449
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Cited by 4 scholarly publications.
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KEYWORDS
Refractive index

Glasses

Pulsed laser operation

Waveguides

Monochromatic aberrations

Picosecond phenomena

Ultrafast lasers

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