Effects of laser-plasma interactions on terahertz radiation from solid targets irradiated by ultrashort intense laser pulses
- Beijing National Laboratory of Condensed Matter Physics, Institute of Physics, CAS, Beijing 100190 (China)
- Purple Mountain Observatory, Chinese Academy of Sciences, Nanjing 210008 (China)
Interactions of 100-fs laser pulses with solid targets at intensities of 10{sup 18} W/cm{sup 2} and resultant terahertz (THz) radiation are studied under different laser contrast ratio conditions. THz emission is measured in the specular reflection direction, which appears to decrease as the laser contrast ratio varies from 10{sup -8} to 10{sup -6}. Correspondingly, the frequency spectra of the reflected light are observed changing from second harmonic dominant, three-halves harmonic dominant, to vanishing of both harmonics. Two-dimensional particle-in-cell simulation also suggests that this observation is correlated with the plasma density scale length change. The results demonstrate that the THz emission is closely related to the laser-plasma interaction processes. The emission is strong when resonance absorption is a key feature of the interaction, and becomes much weaker when parametric instabilities dominate.
- OSTI ID:
- 21611752
- Journal Information:
- Physical Review. E, Statistical, Nonlinear, and Soft Matter Physics (Print), Vol. 84, Issue 3; Other Information: DOI: 10.1103/PhysRevE.84.036405; (c) 2011 American Institute of Physics; Country of input: International Atomic Energy Agency (IAEA); ISSN 1539-3755
- Country of Publication:
- United States
- Language:
- English
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71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
COMPUTERIZED SIMULATION
HARMONICS
LASERS
PARAMETRIC INSTABILITIES
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PLASMA DENSITY
PULSES
RESONANCE ABSORPTION
TWO-DIMENSIONAL CALCULATIONS
ABSORPTION
INSTABILITY
OSCILLATIONS
PLASMA INSTABILITY
PLASMA MACROINSTABILITIES
SIMULATION
SORPTION