Propagation of laser beams formed by unstable resonators with different magnifications
Bibliographic record
Abstract
Laser beams generated from high-magnification on-axis unstable resonators using hard-edged axial scraper mirrors and output couplers consisting of axial spot reflectors typically have an annular distribution in the near field (i.e., a flat-top profile with a hole in the middle for an axially coupled beam). We employ a new model, based on the flattened Gaussian beam (FGB) concept, to describe the propagation of such annular near-field beams. The superposition of two FGBs, whose flatness and steepness of edges are controlled by defined parameters (i.e., the beam width and the order), is used to analyze the output beam intensity profile along the propagation axis. We apply this model to characterize the output beams of copper vapour lasers employing unstable resonators of different magnifications (M = 80, 200, and 400). We show that once the model is fitted to the beam intensity profile at any two positions along the axis of propagation, it can be used to predict the beam shape at any position.PACS Nos.: 42.55.–f, 42.55.Lt, 42.60.–v
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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 | 0.001 |
| Meta-epidemiology (narrow) | 0.001 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.001 | 0.000 |
| Science and technology studies | 0.000 | 0.001 |
| Scholarly communication | 0.001 | 0.001 |
| 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".