Quantum interference control of free-carrier density in GaAs
Bibliographic record
Abstract
We have carried out theoretical and experimental investigations of optical phase controlled-free carrier injection in semiconductors via quantum interference between different absorption pathways connecting the same initial and final states in the valence and conduction bands. The interference schemes are theoretically modeled within a Fermi Golden rule approximation which also allows for a description in terms of the susceptibility formalism of nonlinear optics. Two different types of schemes involving interference between n and m multiphoton absorption events are considered depending on whether $n+m$ is even or odd. If $n+m$ is odd, phase control of carrier density can be observed only in a noncentrosymmetric crystal; if $n+m$ is even, interference can be observed in both centrosymmetric and noncentrosymmetric materials. The interference contribution to the density control is related to the imaginary part of the nonlinear electric susceptibility ${\ensuremath{\chi}}_{n+m\ensuremath{-}1}.$ Experimentally we have investigated carrier density control effects in GaAs at room temperature using nominally 150 fs optical pulses and considered an example for each of the two schemes: one-photon vs two-photon absorption with 0.775 and $1.55\ensuremath{\mu}\mathrm{m}$ pulses and one-photon vs three-photon absorption with 0.675 and $2.03\ensuremath{\mu}\mathrm{m}$ pulses. The main experimental features, including degree of phase control, are in good agreement with theory. We extract the relative magnitude of the imaginary and real components of ${\ensuremath{\chi}}_{2}$ and ${\ensuremath{\chi}}_{3}$ for GaAs at $1.55\ensuremath{\mu}\mathrm{m}$ and $2.03\ensuremath{\mu}\mathrm{m},$ respectively.
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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) | 0.004 | 0.001 |
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".