Femtosecond laser-induced refractive index modifications in fluoride glass
Bibliographic record
Abstract
The interaction of focused 800 nm femtosecond (fs) laser pulses at low (1–45 kHz) and moderate (50–250 kHz) repetition rates with fluoride (ZBLAN-type) bulk glass is investigated in detail. It is shown that at repetition rates lower than ~50 kHz and low pulse energies, the refractive index change induced by pulse filamentation is mainly negative at the irradiated zone. At repetition rates above 50 kHz, structures are formed as a result of the fs laser pulse induced heat accumulation and subsequent melting of the glass. The refractive index profile of the structures produced in this regime is influenced by the laser writing conditions (repetition rate, pulse energy and translation speed). It is shown that waveguides with large circular cross sections and smooth positive index changes can be formed through a precise control of glass exposure. Those waveguides can exhibit low propagation losses (~0.4–2 dB/cm) and are thus good candidates for the development of mid-IR integrated photonic devices. Both absorbed energy and repetition rate thresholds for heat accumulation are determined experimentally.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.001 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".