Coherent stitching of light in femtosecond laser formed multi-layered volume gratings
Bibliographic record
Abstract
Diffractive Optical Elements serve in complex light systems for enhancing control of beam shaping, pulse shaping, microscopy, optical tweezers and 3D imaging. Multi-layered diffractive elements such as photorefractive volume gratings and computer-generated holograms further offer phase and amplitude modulation, but have been challenging to fabricate and are limited by weak diffraction. To this end, femtosecond lasers have been attractive to pattern refractive index structures inside transparent materials, creating 3D optical circuits and diffractive optics with new types of form-birefringence. However, such flexible writing is burdened with limited resolution and low phase contrast from positive and negative index zones. In this paper, we show that the principle of cascading diffractive structures to accumulate stronger phase contrast breaks down for weak gratings, particularly when the phase elements shrink to the optical wavelength.
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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 | 0.001 |
| Scholarly communication | 0.000 | 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".