Systematic studies of two-color pump-induced high-order harmonic generation in plasma plumes

Ganeev, R. A.; Singhal, H.; Naik, P. A.; Chakera, J. A.; Vora, H.; Khan, R. A.; Gupta, P. D.

doi:10.1103/physreva.82.053831

Cited by 33 publications

(15 citation statements)

References 21 publications

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“…In our approach, the typical driving field intensity is in the order of 10 12 ∼ 10 13 W/cm 2 , which is lower than the typical driving field intensity (in the order of 10 14 W/cm 2 ∼ 10 15 W/cm 2 ) used in other methods for THz generation and/or HHG by two-color laser 8,22,24 . One should also use a long driving laser pulse [much longer than its period (2π/ω 0 )] as that used in Ref.…”

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confidence: 84%

“…Interestingly, the second laser field with frequency 4ω 0 leads to the appearance of 2nth harmonics (even for n = 1) and the associated hyper-Raman line (in particular the 0th hyper-Raman line) as predicted by our theory, since the second laser with frequency 4ω 0 breaks the spatial-temporal symmetry generated by Q 1 . Using this mechanism, we can explain the experimental results of observing even harmonics in helium or plasma plumes (containing nanoparticles, carbon nanotubes, etc) driven by a two-color laser, 22 where the second-harmonic driving term, despite being very small, breaks the symmetry and thus allows additional strong even harmonic components. Our theory also naturally explains the generation of even harmonics and associated hyper-Raman lines by breaking the spatial symmetry 23 .…”

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confidence: 99%

“…One should also use a long driving laser pulse [much longer than its period (2π/ω 0 )] as that used in Ref. [22]. The emitted hyper-Raman line frequency can not only be tuned by the driving field intensity as seen in Fig.…”

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confidence: 99%

“…Our non-perturbative analysis and calculation show that one only needs to tune the intensity of the two-color laser for typical two-level quantum systems, which is very convenient in experiments. We may be able to obtain tunable THz radiation due to the availability of stable, tunable driving sources above the THz regime 1,22 . Moreover, people have already observed even harmonics in experiments with two-color laser 22,24 .…”

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confidence: 99%

“…We may be able to obtain tunable THz radiation due to the availability of stable, tunable driving sources above the THz regime 1,22 . Moreover, people have already observed even harmonics in experiments with two-color laser 22,24 . Therefore it is quite likely that the 0th hyperRaman line (in THz regime) associated with 0th harmonic can be obtained in experiment if our optimization method is used.…”

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confidence: 99%

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Terahertz wave generation from hyper-Raman lines in two-level quantum systems driven by two-color lasers

Zhang¹,

Guo²,

Duan³

et al. 2013

Opt. Express

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Based on spatial-temporal symmetry breaking mechanism, we propose a novel scheme for terahertz (THz) wave generation from hyper-Raman lines associated with the 0th harmonic (a particular even harmonic) in a two-level quantum system driven by two-color laser fields. With the help of analysis of quasi-energy, the frequency of THz wave can be tuned by changing the field amplitude of the driving laser. By optimizing the parameters of the laser fields, we are able to obtain arbitrary frequency radiation in the THz regime with appreciable strength (as strong as the typical harmonics). Our proposal can be realized in experiment in view of the recent experimental progress of even-harmonics generation by two-color laser fields.PACS numbers: 42.65. Ky, 42.50.Hz, 78.20.Bh Introduction Terahertz (THz) radiation, electromagnetic radiation with typical frequency from 0.1 THz to 10 THz-lying in the spectrum gap between the infrared and microwaves, has varieties of applications in information and communication technology, biology and medical sciences, homeland security, and global environmental monitoring etc.1 . The generation of THz wave is a challenge problem due to the lack of appropriate materials with small bandgaps in the usual optical approach. Great effort has been made to the design of THz sources 2-15 . THz wave can be obtained by both electronic and optical methods. The uni-travelling-carrier photodiode 6 and the quantum cascade laser 9-13 are two examples. The electronic approach is limited in the low frequency end of the THz regime, and the optical approach usually focuses on the cases of small energy gap. Technological innovation in photonics and nanotechnology has provided us more new ways for THz radiation generation. Recently an interesting approach based on semiconductor nanostructure driven by acoustic wave was suggested 16 , and electrically pumped photonic-crystal THz laser was developed 17 . THz wave generation by up conversion method through high-order harmonics generation(HHG) in semiconductor quantum dot(QD) was also suggested in our previous work 18 .

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confidence: 84%

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confidence: 99%

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confidence: 99%

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confidence: 99%

mentioning

confidence: 99%

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Terahertz wave generation from hyper-Raman lines in two-level quantum systems driven by two-color lasers

Zhang¹,

Guo²,

Duan³

et al. 2013

Opt. Express

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Generation of harmonics of laser radiation in plasmas

Ganeev

2012

Laser Phys. Lett.

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The review of studies of the high-order harmonic generation of laser radiation in laser-produced plasma describes the developments in this field during last half decade. We show that this approach in frequency conversion of laser radiation towards the extreme ultraviolet range became matured during multiple sets of studies carried out in many laboratories worldwide and demonstrated new opportunities for efficient generation of strong coherent short-wavelength radiation. Harmonic intensity, arb. units ×10 4 0 1 2 3 4 5 40 50 60 70 80 90 Wavelength, nm Carbon aerogel 9H 11H 13H 15H 17H 19HComparison of the HHG spectra of carbon aerogel plasma in the cases of single color pump (thin curves) and two color pump (thick curves) Early studies of plasma-induced harmonicsThe high-order harmonic generation (HHG) from moderate-level femtosecond laser pulses allows producing coherent radiation in the extreme ultraviolet (XUV) spectral range. During last twenty-five years, predominantly rare gases were employed as target media for HHG, which, however, imposed some physical and practical limits on the performance of these coherent XUV sources. So far only low conversion efficiencies of HHG have been reported using gases as the nonlinear media, despite the enormous efforts. For practical applications of high-order harmonic sources, higher conversion efficiency and thus an increase in the photon flux and also of the maximum photon energy of the harmonic radiation would be beneficial. The generation of high-order harmonics in laser-produced plasmas, being for this purpose a relatively new and largely unexplored medium, promises to yield these advances.The application of laser plasma as a nonlinear optical medium for frequency conversion came up at the beginning of nineties with the aim to optimize HHG light sources. The idea was based on the use of larger ionization potentials of alkali ions as compared to noble gases. The use of such plasma was aimed to improve the HHG phase matching conditions, increase the concentration of excited ions and neutrals in plasma, which thought to be a right way for amendments of harmonic yield. In the meantime, those first experiments on HHG in the passage of laser ra-

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