Diversity and slow dynamics of diffraction rings: a comprehensive study of spatial self-phase modulation in a photopolymer
Bibliographic record
Abstract
Spatial self-phase modulation of a Gaussian beam in a photopolymer generated diffraction rings that propagated over unusually long distances (≫Rayleigh length) in the medium. Self-phase modulation was examined under negative, positive, and infinite wavefront curvatures (R) over different pathlengths. Resulting diffraction rings exhibited previously unobserved, slow dynamics, which could be directly monitored at the sample exit face. This study complements but differs fundamentally from previous ones that were predominantly carried out in thin films (≤Rayleigh length) and generated static diffraction rings, which were propagated through air and imaged in the far-field. In the photopolymer, an input beam with R<0 generated diffraction rings with a dark center, which propagated through the medium while increasing in number, underwent filamentation, and finally transformed into a stable self-trapped beam. Diffraction rings generated under R>0 bore a bright center and cyclically exchanged intensity with proximal diffraction rings. Statistical analyses of self-phase modulation at R=∞ identified diffraction rings, which (i) were superimposed with high order modes of a co-propagating self-trapped beam, (ii) resembled fingerprint-like rings, (iii) emerged sequentially, and (iv) possessed a bright center. Results were rationalized by combining self-phase modulation theory with the evolution of refractive index changes in the photopolymer. The findings expose a new facet of spatial self-phase modulation and the complex dynamics of diffraction rings that propagate over long distances.
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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) | 0.000 | 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".