Optical cooling of a Yb-doped alumino-phosphosilicate fiber in air by −250 mK
Bibliographic record
Abstract
Recent progress in the fabrication of Yb-doped silicate fibers with low concentration quenching and low background absorption loss has led to the demonstration of anti-Stokes-fluorescence cooling in several aluminosilicate compositions. This breakthrough is critical to combat deleterious thermal effects due to the quantum defect in fiber lasers and amplifiers. Since cooling efficiencies remain low (1-2.7%), it is paramount to engineer compositions that improve this metric. We report a silica fiber with a core glass heavily doped with aluminum and phosphorus that sets, to our knowledge, a few new records. This few-mode fiber (16-µm core) was cooled in air by -0.25 K from room temperature with ∼0.5 W of 1040-nm power. The measured cooling efficiency is 3.3% at low pump power and 2.8% at the power that produced maximum cooling. The critical quenching concentration inferred from the measured dependence of cooling on pump power and careful calibration of the pump absorption and saturation is 79 wt.%. The inferred background absorption loss is 15 dB/km. Together with the fiber's average Yb concentration of 4.2 wt.%, these metrics rank among the best reported in a silica glass.
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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".