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Strong nonlinear optical effects in micro-confined atmospheric air
- Source :
- Photonics Research, Photonics Research, OSA Publishing, 2019, ⟨10.1364/PRJ.7.001134⟩
- Publication Year :
- 2019
- Publisher :
- The Optical Society, 2019.
-
Abstract
- International audience; Historically, nonlinear optical phenomena such as spectral broadening by harmonic generation have been associated with crystals owing to their strong nonlinear refractive indices, which are in the range of ∼10 −14 cm 2 ∕W. This association was also the result of the limited optical power available from early lasers and the limited interaction length that the laser-crystal interaction architecture could offer. Consequently, these limitations disqualified a large number of materials whose nonlinear coefficient is lower than n 2 ∼10 −16 cm 2 ∕W as suitable materials for nonlinear optics applications. For example, it is a common practice in most of optical laboratories to consider ambient or atmospheric air as a "nonlinear optically" inert medium due to its very low nonlinear coefficient (∼10.10 −19 cm 2 ∕W) and low density. Today, the wide spread of high-power ultra-short pulse lasers on one hand, and low transmission loss and high-power handling of Kagome hollow-core photonic crystal fiber on the other hand, provide the necessary ingredients to excite strong nonlinear optical effects in practically any gas media, regardless of how low its optical nonlinear response is. By using a single table-top 1 mJ ultra-short pulse laser and an air exposed inhibited-coupling guiding hollow-core photonic crystal fiber, we observed generation of supercontinuum and third harmonic generation when the laser pulse duration was set at 600 fs and Raman comb generation when the duration was 300 ps. The supercontinuum spectrum spans over ∼1000 THz and exhibits a typical spectral-density energy of 150 nJ/nm. The dispersion profile of inhibited-coupling hollow-core fiber imprints a distinctive sequence in the supercontinuum generation, which is triggered by the generation of a cascade of four-wave mixing lines and concluded by solitonic dynamics. The Raman comb spans over 300 THz and exhibits multiple sidebands originating from N 2 vibrational and ro-vibrational Raman transitions. With the growing use of hollow-core photonic crystal fiber in different fields, the results can be applied to mitigate air nonlinear response when it is not desired or to use ambient air as a convenient nonlinear medium.
- Subjects :
- Materials science
hollow core fibers, nonlinear optics, photonics crystal fiber
business.industry
Physics::Optics
Nonlinear optics
Optical power
02 engineering and technology
021001 nanoscience & nanotechnology
Laser
01 natural sciences
Atomic and Molecular Physics, and Optics
Electronic, Optical and Magnetic Materials
Supercontinuum
law.invention
010309 optics
law
Nonlinear medium
0103 physical sciences
Dispersion (optics)
[SPI.OPTI]Engineering Sciences [physics]/Optics / Photonic
Optoelectronics
High harmonic generation
0210 nano-technology
business
Photonic-crystal fiber
Subjects
Details
- ISSN :
- 23279125
- Volume :
- 7
- Database :
- OpenAIRE
- Journal :
- Photonics Research
- Accession number :
- edsair.doi.dedup.....19ab70b513c2c5cf0fa8ed85891785e2