Characteristics of femtosecond second-harmonic generation in periodically poled lithium niobate
Why this work is in the frame
A frame that forgets how it found something cannot be audited. These are the routes that admitted this work.
Bibliographic record
Abstract
The temporal and spectral characteristics of femtosecond second-harmonic-generation (SHG) in quasi-phase-matched (QPM) periodically poled lithium niobate (PPLN) are investigated experimentally and theoretically. In the experiments, we studied SHG in PPLN waveguides with different device design and fabrication conditions by adopting ~100-fs optical pulses with different peak powers in the 1.55-μm band. Large phase modulation and spectral broadening of the fundamental wave, and a shift of the centre frequency of the second-harmonic wave were observed when the peak power of the fundamental wave was high enough. Saturation of the conversion efficiency was also observed, which depends on fundamental pulse width and peak power. These phenomena could be attributed to nonlinear phase accumulation under large group-velocity mismatch. In the theory, evolutions of pulse waveforms and optical spectra were studied for both the fundamental and second-harmonic pulses by solving the coupled-mode equations. The simulation results are in good agreement with the experimental data.
Fetched live from OpenAlex and de-inverted. Abstracts are not stored in this database: the inverted indexes are 8.6 GB of the frame’s 9.3 GB of text, and the host has 13 GB free.
Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| 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 it