Scaling up and parametric characterization of two-color air plasma terahertz source

Saxena, Sonal; Bagchi, Suman; Tayyab, M.; Rao, Balaji M.; Kumar, Saurabh; Gupta, Devki Nandan; Chakera, J. A.

doi:10.1088/1555-6611/ab67cc

Cited by 6 publications

(4 citation statements)

References 70 publications

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“…As such, the development of THz filamentation [24,25], soliton propagation [26], harmonic generation [27][28][29], electromagnetically induced transparency [30], etc., promise a bright future for the field. Plasma-based sources have been at the forefront of the development of bright THz sources because they provide broadband and high-intensity methods of THz generation [18,[31][32][33][34][35].…”

Section: Introductionmentioning

confidence: 99%

Local measurement of terahertz field-induced second harmonic generation in plasma filaments

Garriga Francis,

Zhang

2023

Front. Optoelectron.

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The concept of Terahertz Field-Induced Second Harmonic (TFISH) Generation is revisited to introduce a single-shot detection scheme based on third order nonlinearities. Focused specifically on the further development of THz plasma-based sources, we begin our research by reimagining the TFISH system to serve as a direct plasma diagnostic. In this work, an optical probe beam is used to mix directly with the strong ponderomotive current associated with laser-induced ionization. A four-wave mixing (FWM) process then generates a strong second-harmonic optical wave because of the mixing of the probe beam with the nonlinear current components oscillating at THz frequencies. The observed conversion efficiency is high enough that for the first time, the TFISH signal appears visible to the human eye. We perform spectral, spatial, and temporal analysis on the detected second-harmonic frequency and show its direct relationship to the nonlinear current. Further, a method to detect incoherent and coherent THz inside plasma filaments is devised using spatio-temporal couplings. The single-shot detection configurations are theoretically described using a combination of expanded FWM models with Kostenbauder and Gaussian Q-matrices. We show that the retrieved temporal traces for THz radiation from single- and two-color laser-induced air-plasma sources match theoretical descriptions very well. High temporal resolution is shown with a detection bandwidth limited only by the spatial extent of the probe laser beam. Large detection bandwidth and temporal characterization is shown for THz radiation confined to under-dense plasma filaments induced by < 100 fs lasers below the relativistic intensity limit. Graphical Abstract

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Section: Introductionmentioning

confidence: 99%

Local measurement of terahertz field-induced second harmonic generation in plasma filaments

Garriga Francis,

Zhang

2023

Front. Optoelectron.

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“…When the time delay of the two-color field is close to zero delay, the phase difference is π/2, which increases the magnitude of the net current, thereby realizing strong terahertz wave radiation [17]. The cross-section of the THz wave gener-ated by the dual-color laser filamentation is Gaussian distribution [18], and the beam divergence angle can be adjusted by changing the diameter and length of the plasma. Recent studies on THz generation using two-color lasers demonstrate that, as the pump laser energy increases, the THz generation energy increases, and when the laser energy continues to increase, secondary ionization occurs, and the THz intensity continues to increase [18][19][20].…”

Section: Introductionmentioning

confidence: 99%

“…The cross-section of the THz wave gener-ated by the dual-color laser filamentation is Gaussian distribution [18], and the beam divergence angle can be adjusted by changing the diameter and length of the plasma. Recent studies on THz generation using two-color lasers demonstrate that, as the pump laser energy increases, the THz generation energy increases, and when the laser energy continues to increase, secondary ionization occurs, and the THz intensity continues to increase [18][19][20]. Finally, due to intensity clamping and THz energy reabsorption in plasmas, the THz energy tends to saturation.…”

Section: Introductionmentioning

confidence: 99%

Anti-Correlated Plasma and THz Pulse Generation during Two-Color Laser Filamentation in Air

Sun

Zhang

et al. 2022

Ultrafast Sci

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The THz generation efficiency and the plasma density generated by a filament in air have been found anti-correlated when pumped by 800 nm+1600 nm two-color laser field. The plasma density near zero delay of two laser pulses has a minimum value, which is opposite to the trend of THz generation efficiency and contradicts common sense. The lower plasma density cannot be explained by the static tunneling model according to the conventional photocurrent model, but it might be attributed to the electron trapping by the excited states of nitrogen molecule. The present work also clarifies the dominant role of the drifting velocity accelerated by the two-color laser field during the THz pulse generation process. The results promote our understanding on the optimization of the THz generation efficiency by the two-color laser filamentation.

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“…To overcome this limitation, plasma is utilized as a nonlinear medium in various schemes employing a strong laser-plasma interaction. Recently, THz radiation from laser-plasma interactions attracted much interest since plasmas can work at arbitrarily high-laser intensity [9]- [13]. Currently, the focused intensity of a short laser pulse can reach up to 10 20 W/cm 2 [14].…”

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confidence: 99%

High-Field Coherent Terahertz Radiation Generation From Chirped Laser Pulse Interaction With Plasmas

Gurjar

Gopal

Gupta

et al. 2020

IEEE Trans. Plasma Sci.

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This article presents a theoretical analysis of high-field terahertz (THz) radiation generation from chirped laser pulse interaction with a plasma of slanting density modulation. The mechanism is based on strong nonlinear transverse current produced by the beating of two chirped laser pulses, where the plasma density modulation is inclined at angle to the propagation of the lasers. We claim that oblique spatial density ripple plays a crucial role in field enhancement of THz. At resonance (due to the phase-matching), the field strength of THz becomes maximum for a particular slating angle of the plasma density modulation. We claim that the oblique spatial density ripple and laser frequency-chirp combinedly play a crucial role in field enhancement of THz field. We observe that stable THz is generated with a maximum field strength of 100 MV/cm and a relatively broad spectrum extending out to 2.4 THz, with a strong dependence on the selection of slating angle of plasma density ripple and laser frequency chirp parameter, which corresponds to the conversion efficiency in order of 10 −2. The efficiency of the process may be optimized and controlled by the laser and plasma parameters, which may be useful in various applications of these kind of high-field THz.

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Scaling up and parametric characterization of two-color air plasma terahertz source

Cited by 6 publications

References 70 publications

Local measurement of terahertz field-induced second harmonic generation in plasma filaments

Local measurement of terahertz field-induced second harmonic generation in plasma filaments

Anti-Correlated Plasma and THz Pulse Generation during Two-Color Laser Filamentation in Air

High-Field Coherent Terahertz Radiation Generation From Chirped Laser Pulse Interaction With Plasmas

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