Single-frequency pulsed laser oscillator and system for laser-ultrasonics
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Bibliographic record
Abstract
Abstract: We present a new pulsed laser oscillator and system for the optical detection of ultrasound in materials. A single-frequency laser oscillator based on a pulse pumped Nd:YAG rod inside a ring cavity is proposed. The laser delivers single-frequency pulses of 35 W power. Power of about 1 kW can be obtained when the second rod of a dual-rod pumping chamber is used as an amplifier. Performance of the system is then investigated with a GaAs photorefractive crystal-based two-wave mixing phase demodulator. In particular, the intensity noise of the laser can be made low enough to allow the detection limit to be set by the shot-noise of the laser. The coherence length of the laser is about 20 m, which makes it a versatile laser-ultrasonic inspection system operated with a two-wave mixing based phase demodulator. A complete compact and affordable system is obtained when the second rod of the pumping chamber is used as a generation laser of ultrasound. Tests of this laser-ultrasonic system on metallic samples are presented. In that case the second rod of the pumping chamber is used as an ultrasound generation laser. Introduction: Laser generation and detection of ultrasound presents numerous advantages for material inspection and characterization over classical piezoelectric-based techniques [1]. In particular, lasers allow probing parts with complex shape in severe conditions, such as high temperature or parts moving at high speed on a production line [2]. A laser-ultrasonic system is typically made of two units, one for generation and another one for detection of
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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 | 0.001 | 0.001 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.001 |
| Science and technology studies | 0.000 | 0.001 |
| 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