Simultaneous elliptically and radially polarized THz from one-color laser-induced plasma filament

Abstract

THz-based technologies and research applications have seen a rapid increment in recent period together with the development of novel radiation sources based both on relativistic electrons and laser techniques. In this framework, laser-induced plasma filament plays an important role in generating intense and broadband THz radiation. Although many attentions have been paid to THz emission from two-color plasma filaments, one-color plasma emission has been scarcely investigated. In particular, the polarization state of one-color THz emission is still controversial due to the limitations of the existing THz detection techniques, which are incapable of simultaneously detecting elliptically and radially polarized THz radiation. In this manuscript, we develop a novel detection method and unambiguously demonstrate for the first time that one-color laser-induced plasma filament simultaneously emits elliptically and radially polarized THz radiation. These polarization states suggest that the generation mechanism results from electric quadrupole, showing a new route for producing more complex polarization states and THz vortex beams.

Ultrafast hole relaxation between dual valence bands in methylammonium lead iodide

“…The ratio between the differential peak change and the static THz peak is proportional to the average real part of the complex photoconductivity across the THz band. 42,52 Here, t eos is the time delay between the THz and the EOS 47 probe; t eos = 0 corresponds to the THz maximum; Δ E ( t eos = 0, t pp ) is the differential transmission of the THz maximum as a function of t pp ; E ref ( t eos = 0) is the peak of the THz waveform transmitted through the unexcited sample. Eqn (3) is employed to calculate the average real photoconductivity versus t pp .…”

“…In the THz generation arm, the beam is further split into two parts by a second beam splitter. Around 10% is reected by the splitter to detect THz electric eld with electro-optic sampling (EOS), 46,47 which is referred to as the EOS probe hereaer. The EOS probe is sent to a retroreector built on a delay line to change the time delay between the EOS probe pulse and the THz pulse.…”

Plasma-based terahertz wave photonics in gas and liquid phases

“…Such a PC can control the polarization and phase of each optical beam individually for coherent control of the THz emission [11] . THz wave emission from biased gas plasma or plasma filaments in ambient air can be classified to the case of single-wavelength laser excitation [20,22,25,46,66,69–79] . The use of single-color few-cycle laser pulses to ionize gases for intense THz wave emission can be classified into both cases [80] , since, very similar to the asymmetric optical fields synthesized from two-color optical fields, a few-cycle laser field itself can produce asymmetric fields by properly controlling the carrier–envelope phase without the involvement of the SH laser field.…”

Terahertz Spectroscopic Analysis in Protein Dynamics: Current Status

“…In the last two decades, many efforts have been made to improve THz technology, e.g., THz sources and detectors [56][57][58][59][60][61][62][63][64][65][66][67][68][69], discovering new materials with strong THz response [70][71][72][73] and new customizable, flexible and compact devices for spectroscopy [74].…”