Three-Photon Absorption in Nanostructure Wide-Band Gap Semiconductor ZnO Using Femtosecond Laser
Bibliographic record
Abstract
The three-photon absorption (3PA) in nanostructure wide-band gap ZnO semiconductor material is observed under high intensity femtosecond Titanium-Sapphire laser of 800 nm wavelength excitation. The ZnO nanofilms were prepared by chemical spray pyrolysis technique with substrate temperature of 370 oC. The optical properties concerning the absorption, transmission, and the photoluminescence spectra are studied for the prepared nanofilms. The structure of the ZnO nanofilm was tested with the X-Ray diffraction and it was found to be a polycrystalline with recognized peaks oriented in (002), (101), and (100). The measured nonlinear absorption coefficient was found to be about 0.062 cm3/Gwatt2, which is about ten time higher than the bulk value. The observation of 3PA under the influence of intense laser radiation was attributed to the two-photon absorption followed by free carrier absorption. The fully computerized z-scan system was used to measure the nonlinear coefficients from the Gaussian fit of the transmitted laser incident. The observation of the three-photon absorption under high intensity in nanocrystalline material attributed to the resonance between the 3hvsph and hvflu which is simply achieved in nanostructure.
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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) | 0.001 | 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".