Femtosecond two-beam coupling energy transfer from Raman and electronic nonlinearities

“…The phase shift of the probe is enhanced by a factor of two regardless of whether the probe is degenerate or nondegenerate with the pump. Similar calculations using higher-order response functions predict enhanced probe phase shifts for the higher-order Kerr effect due to χ (5) , χ (7) , etc. [10].…”

Section: A Electronic Nonlinearitymentioning

confidence: 66%

“…Depending on the relative phase between the diffracted pump beam light and the probe beam, the probe can experience a phase shift and/or an amplitude change [7]. This is the physical mechanism responsible for the enhanced phase shift in cross phase modulation compared to self-phase modulation.…”

Section: Introductionmentioning

confidence: 99%

Effect of two-beam coupling in strong-field optical pump-probe experiments

et al. 2013

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Nonlinear optics experiments measuring phase shifts induced in a weak probe pulse by a strong pump pulse must account for coherent effects that only occur when the pump and probe pulses are temporally overlapped. It is well known that a weak probe beam experiences a greater phase shift from a strong pump beam than the pump beam induces on itself. The physical mechanism behind the enhanced phase shift is diffraction of pump light into the probe direction by a nonlinear refractive index grating produced by interference between the two beams. For an instantaneous third-order response, the effect of the grating is to simply double the probe phase shift, but when delayed nonlinearities are considered, the effect is more complex. A comprehensive treatment is given for both degenerate and nondegenerate pump-probe experiments in noble and diatomic gases. Results of numerical calculations are compared to a recent transient birefringence measurement [Loriot et al., Opt. Express 17, 13429 (2009)] and a recent spectral interferometry experiment [Wahlstrand et al., Phys. Rev. A 85, 043820 (2012)]. We also present results from two new experiments using spectrally-resolved transient birefringence with 800 nm pulses in Ar and air and degenerate chirped pulse spectral interferometry in Ar. Both experiments support the interpretation of the negative birefringence at high intensity as arising from a plasma grating. arXiv:1302.3208v2 [physics.optics]

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“…The observation of anomalous dispersion associated with negative pre-chirp requires us to consider a different nonlinear process. Smolorz et al considered two-beam coupling for chirped pulses [20], and indicate energy is transferred from high-frequency to low frequency components during the interaction. Energy transfer depends on phase matching and depends on the relative time delay between the chirped pulses.…”

Section: Resultsmentioning

confidence: 99%

Anomalous laser-induced group velocity dispersion in fused silica

et al. 2013

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We present 20fs(2) accuracy laser-induced group velocity dispersion (LI-GVD) measurements, resulting from propagation of a femtosecond laser pulse in 1mm of fused silica, as a function of peak intensity. For a 5.5 × 10(11) W/cm(2) peak intensity, LI-GVD values are found to vary from -3 to + 15 times the material GVD. Normal induced dispersion can be explained by the Kerr effect, but anomalous LI-GVD, found when the input pulses have negative pre-chirp, cannot. These findings have significant implications regarding self-compression and the design of femtosecond lasers.

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Femtosecond two-beam coupling energy transfer from Raman and electronic nonlinearities

Cited by 42 publications

References 12 publications

Experimental observation of a traveling plasma grating formed by two crossing filaments in gases

Experimental observation of a traveling plasma grating formed by two crossing filaments in gases

Effect of two-beam coupling in strong-field optical pump-probe experiments

Anomalous laser-induced group velocity dispersion in fused silica

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