High-order solid-surface harmonics for sub-femtosecond pulse generation
Bibliographic record
Abstract
Past works have used high-order harmonics in gas targets to demonstrate attosecond pulse generation. However, recent theoretical simulations have shown that solid-surface harmonics can also be used to produce attosecond pulses. Solid-surface harmonics are generated when a high-intensity femtosecond laser pulse irradiates a solid target surface at an oblique incidence angle. The conversion efficiency of this phenomenon increases rapidly with increasing pump laser intensity, and there is also no presently known upper limit in the pump intensity that can be used. Accordingly, this method possesses the potential for high-energy attosecond pulse generation. The main aim of this paper is to experimentally clarify the optimal conditions for highly efficient solid-surface harmonic generation. We demonstrate up to the 16th harmonic (49.1 nm wavelength) of a Ti:sapphire laser using modest pump intensities of 4×1016 W cm-2 irradiating a silicon wafer target. Investigations with low-order harmonics have revealed a large dependence of harmonic conversion efficiency on the target material. Furthermore, a drastic increase in the harmonic intensity has been observed by repetitively irradiating a metallic-coated target.
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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 | 0.001 |
| Insufficient payload (model declined to judge) | 0.003 | 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".