Abstract
Present study focuses on self-focusing and its effect on third harmonic generation (THG) of a Gaussian laser beam in plasma under the influence of exponential density ramp. Relativistic nonlinearity has been taken into account which is aroused due the modification of electron’s mass in the presence of high intensity laser. Under strong ponderomotive force, electrons acquire very high quiver velocity and mass variation takes place. Equations for beam width parameter of incident laser and the amplitude of THG have been derived under WKB and paraxial ray approximation, and solved them numerically. It is found that the presence of exponential plasma density ramp results strong self-focusing of laser which further leads to enhance the efficiency of THG. Wiggler magnetic field adds an additional momentum to the photons of third harmonic due to which appreciable gain is observed in the normalized amplitude of THG. Significant enhancement in the THG amplitude has been reported in the presence of exponential density ramp for optimum values of intensity of incident laser, wiggler magnetic field and plasma frequency.
Funding source: Science and Engineering Research Board
Award Identifier / Grant number: TAR/2018/000916
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Author contribution: All the authors have accepted responsibility for the entire content of this submitted manuscript and approved submission.
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Research funding: This work is supported by the TARE Scheme (Grant No. TAR/2018/000916) of SERB, DST, New Delhi, India.
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Conflict of interest statement: The authors declare no conflicts of interest regarding this article.
References
[1] J. Parashar and H. D. Pandey, “Second-harmonic generation of laser radiation in a plasma with a density ripple,” IEEE Trans. Plasma Sci., vol. 20, p. 996, 1992. https://doi.org/10.1109/27.199564.Search in Google Scholar
[2] T. Tajima and J. M. Dawson, “Laser electron accelerator,” Phys. Rev. Lett., vol. 43, p. 267, 1979. https://doi.org/10.1103/physrevlett.43.267.Search in Google Scholar
[3] C. G. R. Geddes, C. Toth, J. Van Tilborg, et al.., “High-quality electron beams from a laser wake-field accelerator using plasma-channel guiding,” Nature, vol. 431, p. 538, 2004. https://doi.org/10.1038/nature02900.Search in Google Scholar PubMed
[4] R. Singh, A. K. Sharma, and V. K. Tripathi, “Relativistic self-distortion of a laser pulse and ponderomotive acceleration of electrons in an axially inhomogeneous plasma,” Laser Part. Beams, vol. 28, p. 299, 2010. https://doi.org/10.1017/s0263034610000200.Search in Google Scholar
[5] A. Chiron, G. Bonnaud, A. Dulieu, et al.., “Experimental observations and simulations on relativistic self‐guiding of an ultra‐intense laser pulse in underdense plasmas,” Phys. Plasmas, vol. 3, p. 1373, 1996. https://doi.org/10.1063/1.871729.Search in Google Scholar
[6] D. Yelin and Y. Silberberg, “Laser scanning third-harmonic-generation microscopy in biology,” Opt. Express, vol. 5, p. 169, 1999. https://doi.org/10.1364/oe.5.000169.Search in Google Scholar PubMed
[7] G. O. Clay, A. C. Millard, C. B. Schaffer, et al.., “Spectroscopy of third-harmonic generation: evidence for resonances in model compounds and ligated hemoglobin,” J. Opt. Soc. Am. B, vol. 23, p. 932, 2006. https://doi.org/10.1364/josab.23.000932.Search in Google Scholar
[8] C. F. Hernandez, S. Y. Tseng, D. Owens, and B. Kippelen, “Ultrafast optical image processing based on third-harmonic generation in organic thin films,” Appl. Phys. Lett., vol. 91, p. 131110, 2007. https://doi.org/10.1063/1.2790826.Search in Google Scholar
[9] V. N. Konopsky, E. V. Alieva, S. Y. Alyatkin, A. A. Melnikov, S. V. Chekalin, and V. M. Agranovich, “Phase-matched third-harmonic generation via doubly resonant optical surface modes in 1D photonic crystals,” Light Sci. Appl., vol. 5, p. 1, 2016. https://doi.org/10.1038/lsa.2016.168.Search in Google Scholar PubMed PubMed Central
[10] V. Sharma, V. Tahkur, and N. Kant, “Third harmonic generation of a relativistic self-focusing laser in plasma in the presence of wiggler magnetic field,” High. Energy Density Phys., vol. 32, p. 51, 2019. https://doi.org/10.1016/j.hedp.2019.04.007.Search in Google Scholar
[11] N. S. Rathore and P. Kumar, “Phase matched third harmonic generation of a Gaussian Laser pulse in high-density quantum plasma,” Am. J. Phys., vol. 5, p. 154, 2016. https://doi.org/10.11648/j.ajmp.20160505.16.Search in Google Scholar
[12] M. D. Feit, A. M. Komashko, and A. M. Rubenchik, “Relativistic self-focusing in underdense plasma,” Physica D, vol. 152, p. 705, 2001. https://doi.org/10.1016/s0167-2789(01)00203-2.Search in Google Scholar
[13] J. Rajput, N. Kant, H. Singh, and V. Nanda, “Resonant third harmonic generation of a short pulse laser in plasma by applying a wiggler magnetic field,” Opt. Commun., vol. 282, p. 4614, 2009. https://doi.org/10.1016/j.optcom.2009.08.042.Search in Google Scholar
[14] C. Rödel, D. Brügge, J. Bierbach, et al.., “Harmonic generation from relativistic plasma surfaces in ultrasteep plasma density gradients,” Phys. Rev. Lett., vol. 109, p. 125002, 2012.10.1103/PhysRevLett.109.125002Search in Google Scholar PubMed
[15] V. Sharma, V. Thakur, and N. Kant, “Hermite-cosh-Gaussian laser-induced third harmonic generation in plasma,” Opt. Quant. Electron., vol. 53, p. 281, 2021. https://doi.org/10.1007/s11082-021-02943-7.Search in Google Scholar
[16] M. Singh and D. N. Gupta, “Relativistic third-harmonic generation of a laser in a self-sustained magnetized plasma channel,” IEEE J. Quant. Electron., vol. 50, p. 491, 2014.10.1109/JQE.2014.2320763Search in Google Scholar
[17] V. Thakur and N. Kant, “Exponential density transition-based enhanced second harmonic generation in plasma,” Laser Part. Beams, vol. 36, p. 363, 2018. https://doi.org/10.1017/s0263034618000393.Search in Google Scholar
[18] D. N. Gupta, “Optical second-harmonic generation of terahertz field from n-type InSb semiconductors,” Plasmonics, vol. 16, p. 419, 2021. https://doi.org/10.1007/s11468-020-01291-8.Search in Google Scholar
[19] M. Singh, D. N. Gupta, and H. Suk, “Efficient second and third-harmonic radiation generation from relativistic laser-plasma interactions,” Phys. Plasmas, vol. 22, 2015, Art no. 063303. https://doi.org/10.1063/1.4922435.Search in Google Scholar
[20] D. N. Gupta, M. S. Hur, I. Hwang, H. Suk, and A. K. Sharma, “Plasma density ramp for relativistic self-focusing of an intense laser,” J. Opt. Soc. Am. B, vol. 24, p. 1155, 2007. https://doi.org/10.1364/josab.24.001155.Search in Google Scholar
[21] D. N. Gupta, K. Avinash, and H. Suk, “Transient self-focusing of an intense laser pulse in magnetized plasmas under non-paraxial approximation,” Laser Part. Beams, vol. 31, p. 307, 2013. https://doi.org/10.1017/s0263034613000177.Search in Google Scholar
[22] V. Thakur, S. Vij, V. Sharma, and N. Kant, “Influence of exponential density ramp on second harmonic generation by a short pulse laser in magnetized plasma,” Optik, vol. 171, p. 523, 2018. https://doi.org/10.1016/j.ijleo.2018.06.086.Search in Google Scholar
[23] V. Thakur and N. Kant, “Resonant second harmonic generation in plasma under exponential density ramp profile,” Optik, vol. 168, p. 159, 2018. https://doi.org/10.1016/j.ijleo.2018.04.073.Search in Google Scholar
[24] V. Thakur and N. Kant, “Effect of pulse slippage on density transition-based resonant third-harmonic generation of short-pulse laser in plasma,” Front. Phys., vol. 11, p. 115202, 2016. https://doi.org/10.1007/s11467-016-0563-8.Search in Google Scholar
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