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We present a novel technique for generating beams of light carrying orbital angular momentum (OAM) that increases mode purity and decreases singularity splitting by orders of magnitude. This technique also works to control and mitigate beam divergence within propagation distances less than the Rayleigh length. Additionally, we analyze a tunable parameter of this technique that can change the ratio of beam purity to power to fit desired specifications. Beam generation via this technique is achievable using only phase-modulating optical elements, which reduces experimental complexity and beam energy loss.
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Analytical approximation of the second-harmonic conversion efficiency
The second-harmonic generation process of a focused laser beam inside a nonlinear crystal is described by the Boyd–Kleinman theory. Calculating the actual conversion efficiency and upconverted power requires the solution to a double integral that is analytically intractable. We provide an expression that predicts the exact gain coefficient within an error margin of less than 2% over several orders of magnitude of the confocal parameter and as a function of the walk-off parameter. Our result allows for readily tuning the beam parameters to optimize the performance of the upconversion process and improve optical system designs.
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- Award ID(s):
- 1839153
- PAR ID:
- 10196031
- Publisher / Repository:
- Optical Society of America
- Date Published:
- Journal Name:
- Applied Optics
- Volume:
- 59
- Issue:
- 28
- ISSN:
- 1559-128X; APOPAI
- Format(s):
- Medium: X Size: Article No. 9010
- Size(s):
- Article No. 9010
- Sponsoring Org:
- National Science Foundation
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