Fringe-averaged collinear frequency-resolved optical gating: in situ characterization of ultrashort pulses in nonlinear microscopy
Bibliographic record
Abstract
In situ characterization of the electric field of ultrafast pulses is critical in multiphoton microscopy. Although second harmonic generation-based collinear Frequency-Resolved Optical Gating (FROG) addresses this need, the interferometric measurement is challenged by interferometric drift instability, the required high sampling density of the acquired data, and the inability to directly use the interferometric data with conventional FROG retrieval algorithms. We address these issues by combining low-pass Fourier filtering with active kHz dithering of the interferometric path length difference using a piezo-driven retroreflector. We demonstrate successful electric field retrieval for pulses of variable duration (∼100 fs-3 ps), in situ characterization of a chirped pulse in a nonlinear microscope, and a significant reduction in acquisition time, without loss of resolution, by undersampling.
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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 | 0.001 |
| 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".