Terahertz emission from ultrafast optical orientation of spins in semiconductors: Experiment and theory
Bibliographic record
Abstract
We discuss the optical injection of magnetization into a nonmagnetic semiconductor by the absorption of circularly polarized light. A microscopic approach, which is based on Fermi's golden rule and $\mathbf{k}\ensuremath{\cdot}\mathbf{p}$ band models, is used to quantify the magnetization-injection rate in GaAs. We find that under conditions typical in optical orientation experiments, the magnetization-injection rate of holes is approximately 20 times larger than it is for electrons, reflecting the large hole magnetic moment. We then turn to the ultrafast excitation regime and explore the possibility that the injected magnetization can radiate a detectable terahertz field. By using a phenomenological approach for the magnetization relaxation dynamics, we predict that the terahertz field from magnetic injection is at the limit of current terahertz detection technology. We provide initial experimental measurements in search of this terahertz radiation.
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How this classification was reachedexpand
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 itClassification
machine, unvalidatedMachine predicted; a candidate call from one teacher head, 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".