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Tailoring Ponderomotive Force for Efficient Terahertz Radiation Emission

par Caroline CHAMPENOIS - publié le

séminaire du laboratoire
mercredi 13 juillet à 11:00, service 361 du campus Saint-Jérôme

Hitendra K. Malik
Indian Institute of Technology (IIT) Delhi, New Delhi – 110 016, INDIA

abstract :

Owing to their enormous applications in medicine, explosive and concealed weapon detection, material characterization, remote sensing, etc., the terahertz (THz) sources and detectors have attracted the researchers all over the world, and an extensive research is going on for their further development and improved versions. In order to generate the THz radiation, the researchers have made use of air, plasmas, metamaterials, semiconductors and electro-optic crystals as different media for their exploitation by lasers in different types of schemes [1 – 8]. We encounter different problems in different techniques of THz emission. For example, the limitations of material based schemes are material damage due to ultra-high intense lasers and low efficiency of the mechanisms. However, such limitations can be overcome if we use plasma in place of solid materials. Plasma as a matter has a strong capacity to hold very high nonlinear currents those are generated as a result of highly nonlinear mechanisms due to laser plasma interaction.
In the present talk, we will discuss some interesting plasma based mechanisms for the emission of THz radiation. At first, the plasma will be introduced as a fourth state of matter, and different kinds of response of the plasma species will be talked about when a strong laser interacts with the plasma. In the next attempt, the role of plasma electrons, ponderomotive force and magnetic field will be uncovered in tuning the frequency, power and direction of emitted THz radiation. The process of achieving the resonance between the laser’s ponderomotive force and generated nonlinear current in the plasma will be discussed. Finally, a comparison of various plasma based mechanisms will be made for the diverse applications of such THz emitters.

[1] H. Zheng et al., Opt. Express 14, 9130 (2006).
[2] H.K. Malik, Phys. Lett. A (2015) 379, 2826 ; Europhys. Lett. 106, 55002 (2014). [3] H.K. Malik and A.K. Malik, Appl. Phys. Lett. 99, 251101 (2011).
[4] D. Singh and H. K. Malik, Plasma Sources Sci. Tech. 24, 045001 (2015). [5] W.M. Wang et al., Phys. Plasmas 18, 073108 (2011).
[6] I. Al-Naib et al., Phys. Rev. B 88, 195203 (2013).
[7] P. Zhao, S. Ragam, Y. J. Ding, and I. B. Zotova, Opt. Lett. 35, 3979 (2010). [8] A. N. Bugay and S. V. Sazonov, Phys. Lett. A 374, 1093 (2010).

contact : Yves Elskens


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