An optoacoustic transfer function for laser-ultrasonics: definition and its characterization for various lasers in the ablation regime
Bibliographic record
Abstract
To maximize the signal-to-noise ratio of a laser-ultrasound system, one may choose to reduce the noise by using a better interferometer(and associated laser, optics, etc.), or to increase the signal by selecting a better generation laser. Given that interferometers have reached the detection limit of photon statistics, we focus our attention on ultrasound generation. To do so, we define an optoacoustic transfer function that describes the ultrasound generation efficiency of a pulsed laser on a specific material in a predetermined frequency bandwidth. On this basis, we compare the generation efficiency of various lasers on metals in the ablation regime. It is found that, at constant fluence, shorter pulses (ps) and shorter radiation wavelengths (UV) generate ultrasound more efficiently than longer pulses (ns) and longer radiation wavelengths (IR). It is also found that the generation efficiency is inversely proportional to frequency, as it should be if the generated ultrasonic pulse is a step function.
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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 | 0.001 | 0.003 |
| Meta-epidemiology (narrow) | 0.001 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.002 | 0.001 |
| Science and technology studies | 0.000 | 0.001 |
| Scholarly communication | 0.001 | 0.001 |
| Open science | 0.001 | 0.000 |
| Research integrity | 0.001 | 0.001 |
| Insufficient payload (model declined to judge) | 0.002 | 0.001 |
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".