Abstract
In this Letter, we demonstrate that the far-field terahertz (THz) beam generated from a Ti:Sapphire two-color laser-induced filament can exhibit a conical or Gaussian distribution, depending on the filtering experimental conditions. Using both an incoherent Golay cell detector and a two-dimensional coherent electro-optic detection covering the 0.2–2.6 THz spectral range, in our experimental conditions, we provide evidence that the conical emission is due to photo-induced carriers in the silicon filter, typically used to block the remaining pump laser light. Moreover, the low-frequency THz beam retrieves an almost TEM00 Gaussian spatial distribution when the silicon filter is preceded by a large bandgap ceramic filter, which stops the pump beam, thus preventing the carrier generation in the silicon filter.
Originalsprog | Engelsk |
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Tidsskrift | Optics Letters |
Vol/bind | 45 |
Udgave nummer | 7 |
Sider (fra-til) | 2132-2135 |
Antal sider | 4 |
ISSN | 0146-9592 |
DOI | |
Status | Udgivet - 2020 |