Photoelectron spectroscopic determination of the energy bandwidths of high-order harmonics (7th–55th) produced by an ultrafast laser in neon
Bibliographic record
Abstract
The energy bandwidths of high-order harmonics of a Ti:sapphire ultrafast laser are extracted from electron kinetic-energy measurements of the photoionization of gas-phase atoms and molecules. High-order harmonics of the 70 fs, 800 nm laser are produced by focusing $\ensuremath{\approx}2.5 \mathrm{mJ}$ pulses into a jet of neon gas and are frequency-separated by a grazing-incidence grating. Photoelectrons resulting from the ionization of gaseous samples are energy-analyzed with a magnetic bottle time-of-flight spectrometer. Energy broadening of the photoelectron peaks at low kinetic energies are a direct result of the energy bandwidths of the harmonics. The energy bandwidths of the harmonics are found to increase from $0.11(\ifmmode\pm\else\textpm\fi{}0.03) \mathrm{eV}$ (7th harmonic) to $0.37(\ifmmode\pm\else\textpm\fi{}0.03) \mathrm{eV}$ (45th harmonic) in a gradual manner. The higher-order harmonics (47th--55th) appear to reach a plateau at a value of $\ensuremath{\approx}0.43 \mathrm{eV}.$ Though a full theoretical treatment of bandwidths of the harmonics for the 70 fs driving pulse regime does not exist, the theories developed for shorter pulses $(<~30 \mathrm{fs})$ can give insight into the observed results.
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| 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) | 0.001 | 0.000 |
Machine scores (provisional)
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Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
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