Journal
OPTICS EXPRESS
Volume 26, Issue 14, Pages 18202-18213Publisher
OPTICAL SOC AMER
DOI: 10.1364/OE.26.018202
Keywords
-
Categories
Funding
- Russian Foundation for Basic Research (RFBR) [18-02-00954, 18-52-16020, 18-32-01000]
- Russian Federation [MK-8562.2016.2]
- Presidium of the Russian Academy of Sciences Program [I.6]
- Students and Researchers Exchange Program in Sciences (STEPS)
- Scholarship of Russian Federation [SP-2453.2018.2]
- program UMNIK of Foundation of assistance to development of small forms of enterprises in scientific-technical sphere (FASIE) [11488GU/2017, 11522GU/2017]
- Photon Frontier Network Program of the Ministry of Education, Culture, Sports, Science, and Technology (MEXT)
- Basis Foundation
Ask authors/readers for more resources
We study angular and frequency-angular distributions of the terahertz (THz) emission of the low-frequency region (0.3-3 THz) from a two-color femtosecond plasma spark experimentally and in three-dimensional numerical simulations. We investigate the dependence of the angular shapes of the THz radiation on focusing conditions and pulse durations by using two laser facilities (pulse durations 35 and 150 fs) for different focusing geometries. Our experiments and simulations show that decrease in the numerical aperture from NA approximate to 0.2 to NA approximate to 0.02 results simultaneously in (I) squeezing of the THz angular distribution and (II) formation of the bright conical emission in the THz range. The moderate focusing NA approximate to 0.05, which forms the relatively narrow unimodal THz angular distribution, is identified as optimal in terms of angular divergence. Numerical simulations with carrier wave resolved show that bright THz ring structures appear at the frequencies >= 2 THz for longer focuses (NA approximate to 0.02), while for optimal focusing conditions NA approximate to 0.05 the conical emission develops at THz frequencies higher than 10 THz. (C) 2018 Optical Society of America under the terms of the OSA Open Access Publishing Agreement.
Authors
I am an author on this paper
Click your name to claim this paper and add it to your profile.
Reviews
Recommended
No Data Available