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Phase distribution of Hermite–Gauss (HG) beams generated by a gas laser is investigated experimentally by studying their interference with a plane wave and diffraction by a single slit by selecting pairs of bright lobes with different phases. Experimentally recorded interference and diffraction profiles support HG mode phase profiles expounded on in this paper. We find that the phase difference between one bright lobe and another is not simply zero orπbut increases (or decreases) uniformly in steps ofπas the number of zeros between them increases, in agreement with analytic function theory. An immediate application of this phase profile is that an HG mode can serve as a phase ruler with bright lobes as markers in steps ofπ.
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Interference effects in harmonic generation induced by focal phase distribution
We have performed macroscopic calculations for the thin medium or low gas density regime and a central gas jet using microscopic numerical solutions of the time-dependent Schrödinger equation. In the case of a spatial phase distribution for broadband Gaussian pulses with a negative Porras factor, our theoretical results show an interference pattern in the angular distribution of below- and near-threshold harmonics, which is not present for the monochromatic Gouy phase distribution. The interference pattern is due to off-center contributions that are in-phase with those at the central points in the focus. The location of the maxima in the interference pattern can be estimated using the well-known double-slit formula with an effective slit separation.
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- Award ID(s):
- 1734006
- PAR ID:
- 10250413
- Publisher / Repository:
- Optical Society of America
- Date Published:
- Journal Name:
- OSA Continuum
- Volume:
- 4
- Issue:
- 7
- ISSN:
- 2578-7519
- Format(s):
- Medium: X Size: Article No. 1897
- Size(s):
- Article No. 1897
- Sponsoring Org:
- National Science Foundation
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