Contrasting levels of absorption of intense femtosecond laser pulses by solids

Prashant Kumar Singh, Y. Q. Cui, Amitava Adak, Amit D. Lad, Gourab Chatterjee, P. Brijesh, Z. M. Sheng, G. Ravindra Kumar

Research output: Contribution to journalArticle

8 Citations (Scopus)

Abstract

The absorption of ultraintense, femtosecond laser pulses by a solid unleashes relativistic electrons, thereby creating a regime of relativistic optics. This has enabled exciting applications of relativistic particle beams and coherent X-ray radiation, and fundamental leaps in high energy density science and laboratory astrophysics. Obviously, central to these possibilities lies the basic problem of understanding and if possible, manipulating laser absorption. Surprisingly, the absorption of intense light largely remains an open question, despite the extensive variations in target and laser pulse structures. Moreover, there are only few experimental measurements of laser absorption carried out under very limited parameter ranges. Here we present an extensive investigation of absorption of intense 30 femtosecond laser pulses by solid metal targets. The study, performed under varying laser intensity and contrast ratio over four orders of magnitude, reveals a significant and non-intuitive dependence on these parameters. For contrast ratio of 10-9 and intensity of 2 × 1019W cm-2, three observations are revealed: preferential acceleration of electrons along the laser axis, a ponderomotive scaling of electron temperature, and red shifting of emitted second-harmonic. These point towards the role of J × B absorption mechanism at relativistic intensity. The experimental results are supported by particle-in-cell simulations.

LanguageEnglish
Article number17870
JournalScientific Reports
Volume5
DOIs
Publication statusPublished - 9 Dec 2015

Fingerprint

pulses
lasers
laboratory astrophysics
relativistic particles
particle beams
astrophysics
electrons
flux density
optics
electron energy
harmonics
scaling
radiation
cells
metals
x rays
simulation

Keywords

  • laser-produced plasmas
  • optics
  • photonics

Cite this

Singh, P. K., Cui, Y. Q., Adak, A., Lad, A. D., Chatterjee, G., Brijesh, P., ... Kumar, G. R. (2015). Contrasting levels of absorption of intense femtosecond laser pulses by solids. Scientific Reports, 5, [17870]. https://doi.org/10.1038/srep17870
Singh, Prashant Kumar ; Cui, Y. Q. ; Adak, Amitava ; Lad, Amit D. ; Chatterjee, Gourab ; Brijesh, P. ; Sheng, Z. M. ; Kumar, G. Ravindra. / Contrasting levels of absorption of intense femtosecond laser pulses by solids. In: Scientific Reports. 2015 ; Vol. 5.
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Singh, PK, Cui, YQ, Adak, A, Lad, AD, Chatterjee, G, Brijesh, P, Sheng, ZM & Kumar, GR 2015, 'Contrasting levels of absorption of intense femtosecond laser pulses by solids' Scientific Reports, vol. 5, 17870. https://doi.org/10.1038/srep17870

Contrasting levels of absorption of intense femtosecond laser pulses by solids. / Singh, Prashant Kumar; Cui, Y. Q.; Adak, Amitava; Lad, Amit D.; Chatterjee, Gourab; Brijesh, P.; Sheng, Z. M.; Kumar, G. Ravindra.

In: Scientific Reports, Vol. 5, 17870, 09.12.2015.

Research output: Contribution to journalArticle

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Singh PK, Cui YQ, Adak A, Lad AD, Chatterjee G, Brijesh P et al. Contrasting levels of absorption of intense femtosecond laser pulses by solids. Scientific Reports. 2015 Dec 9;5. 17870. https://doi.org/10.1038/srep17870