Details
| Original language | English |
|---|---|
| Article number | 103038 |
| Journal | New journal of physics |
| Volume | 22 |
| Issue number | 10 |
| Publication status | Published - 16 Oct 2020 |
Abstract
We study the influence of the polarization states of ionizing femtosecond two-color pulses on the emitted terahertz radiation in gases. A local-current model and plane-wave evaluations justify the previously-reported impact on the THz energy yield and a (almost) linearly-polarized THz field when using circularly-polarized laser harmonics. For such pump pulses, the THz yield is independent of the relative phase between the two colors. When the pump pulses have same helicity, the increase in the THz yield is associated with longer ionization sequences and higher electron transverse momenta acquired in the driving field. Reversely, for two color pulses with opposite helicity, the dramatic loss of THz power comes from destructive interferences driven by the highly symmetric response of the photocurrents lined up on the third harmonic of the fundamental pulse. While our experiments confirm an increased THz yield for circularly-polarized pumps of same helicity, surprisingly, the emitted THz radiation is not linearly-polarized. This effect is explained by means of comprehensive 3D numerical simulations highlighting the role of the spatial alignment and non-collinear propagation of the two colors.
Keywords
- filamentation, plasma, polarization control, terahertz generation, ultrashort pulse propagation
ASJC Scopus subject areas
- Physics and Astronomy(all)
- General Physics and Astronomy
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In: New journal of physics, Vol. 22, No. 10, 103038, 16.10.2020.
Research output: Contribution to journal › Article › Research › peer review
}
TY - JOUR
T1 - Terahertz pulse generation by two-color laser fields with circular polarization
AU - Tailliez, C.
AU - Stathopulos, A.
AU - Skupin, S.
AU - Buožius, D.
AU - Babushkin, I.
AU - Vaičaitis, V.
AU - Bergé, L.
PY - 2020/10/16
Y1 - 2020/10/16
N2 - We study the influence of the polarization states of ionizing femtosecond two-color pulses on the emitted terahertz radiation in gases. A local-current model and plane-wave evaluations justify the previously-reported impact on the THz energy yield and a (almost) linearly-polarized THz field when using circularly-polarized laser harmonics. For such pump pulses, the THz yield is independent of the relative phase between the two colors. When the pump pulses have same helicity, the increase in the THz yield is associated with longer ionization sequences and higher electron transverse momenta acquired in the driving field. Reversely, for two color pulses with opposite helicity, the dramatic loss of THz power comes from destructive interferences driven by the highly symmetric response of the photocurrents lined up on the third harmonic of the fundamental pulse. While our experiments confirm an increased THz yield for circularly-polarized pumps of same helicity, surprisingly, the emitted THz radiation is not linearly-polarized. This effect is explained by means of comprehensive 3D numerical simulations highlighting the role of the spatial alignment and non-collinear propagation of the two colors.
AB - We study the influence of the polarization states of ionizing femtosecond two-color pulses on the emitted terahertz radiation in gases. A local-current model and plane-wave evaluations justify the previously-reported impact on the THz energy yield and a (almost) linearly-polarized THz field when using circularly-polarized laser harmonics. For such pump pulses, the THz yield is independent of the relative phase between the two colors. When the pump pulses have same helicity, the increase in the THz yield is associated with longer ionization sequences and higher electron transverse momenta acquired in the driving field. Reversely, for two color pulses with opposite helicity, the dramatic loss of THz power comes from destructive interferences driven by the highly symmetric response of the photocurrents lined up on the third harmonic of the fundamental pulse. While our experiments confirm an increased THz yield for circularly-polarized pumps of same helicity, surprisingly, the emitted THz radiation is not linearly-polarized. This effect is explained by means of comprehensive 3D numerical simulations highlighting the role of the spatial alignment and non-collinear propagation of the two colors.
KW - filamentation
KW - plasma
KW - polarization control
KW - terahertz generation
KW - ultrashort pulse propagation
UR - http://www.scopus.com/inward/record.url?scp=85095724821&partnerID=8YFLogxK
U2 - 10.1088/1367-2630/abb863
DO - 10.1088/1367-2630/abb863
M3 - Article
AN - SCOPUS:85095724821
VL - 22
JO - New journal of physics
JF - New journal of physics
SN - 1367-2630
IS - 10
M1 - 103038
ER -