Quasi-phase matched second-harmonic generation from asymmetric coupled quantum wells
Bibliographic record
Abstract
Quasi-phase matched (QPM) second-harmonic (SH) generation in both insulator and semiconductor waveguides has applications ranging from the generation of coherent visible light to optical signal processing. QPM compensates the wavevector mismatch between the fundamental and SH light by periodically varying the SH susceptibility, /spl chi//sup (2)/, and refractive index, along the SH light propagation direction. It would be very useful if quantum wells could be used to engineer materials with a large /spl chi//sup (2)/ which can be easily varied. Large asymmetric quantum well SH susceptibilities have been measured for far infrared wavelengths, where the nonlinear response is dominated by intra-subband transitions. Although there have been several theoretical studies predicting a quantum well /spl chi//sup (2)/ comparable to that of LiNbO/sub 3/ or larger in the near infrared and visible wavelength range, there have been no experimental measurements of /spl chi//sup (2)/. The authors use reflection geometry QPM to selectively enhance the SH signal from an asymmetric coupled quantum well (ACQW) superlattice. In addition they present the first measurement, to the best of their knowledge, of /spl chi//sup (2)/ in the visible wavelength range for an ACQW.>
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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 | 0.001 |
| Open science | 0.001 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.002 | 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".