Preference of subpicosecond laser pulses for terahertz wave generation from liquids

Jin, Qi; Yiwen, E; Gao, Shenghan; Zhang, X.-C.

doi:10.1117/1.ap.2.1.015001

Cited by 37 publications

(26 citation statements)

References 57 publications

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“…Conventional polarization shapers working in the terahertz electromagnetic frequency range are mainly segmental waveplates and metasurfaces, 11,12 both of which can be well applied for narrow bandwidth applications and low tolerance of flexible tunability. Various scalar manipulations of terahertz waves have been demonstrated in poled nonlinear optical crystals 13,14 or even in water 15 and have synthesized different frequencies generated in spatially distributed sources. 16 However, it would be much more elegant if polarization shaping functionality could be vectorized and integrated into the sources.…”

Section: Introductionmentioning

confidence: 99%

Generation and manipulation of chiral terahertz waves in the three-dimensional topological insulator Bi2Te3

et al. 2020

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Arbitrary manipulation of broadband terahertz waves with flexible polarization shaping at the source has great potential in expanding numerous applications, such as imaging, information encryption, and all-optical coherent control of terahertz nonlinear phenomena. Topological insulators featuring unique spinmomentum-locked surface state have already exhibited very promising prospects in terahertz emission, detection, and modulation, which may lay a foundation for future on-chip topological insulator-based terahertz systems. However, polarization-shaped terahertz emitters based on topological insulators with an arbitrarily manipulated temporal evolution of the amplitude and the electric-field vector direction have not yet been explored. We systematically investigated the terahertz radiation from topological insulator Bi 2 Te 3 nanofilms driven by femtosecond laser pulses and successfully realized the generation of efficient chiral terahertz waves with controllable chirality, ellipticity, and principal axis. The convenient engineering of the chiral terahertz waves was interpreted by a photogalvanic effect (PGE)-induced photocurrent, while the linearly polarized terahertz waves originated from linear PGE-induced shift currents. Our work not only provides further understanding of femtosecond coherent control of ultrafast spin currents but also describes an effective way to generate spin-polarized terahertz waves at the source.

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Section: Introductionmentioning

confidence: 99%

Generation and manipulation of chiral terahertz waves in the three-dimensional topological insulator Bi2Te3

et al. 2020

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“…It turns out that the first observation is the advantage of shorter pulses in double-pulse excitation experiments. The presence of an optimal duration value in single-pulse experiments was earlier interpreted through the combined effect of the electron density exponential growth due to the cascade ionization and pulse energy attenuation with the increase in pulse duration 11 . The double-pump case is indeed different; it seems reasonable to assume that the optimal pulse duration will experience a shift towards lower values since the important moment is not the effective ionization of the molecules, but rather the strong interaction with a pre-ionized medium.…”

Section: Resultsmentioning

confidence: 99%

“…The main directions of the laser-driven plasma terahertz source development are the search for an optimal generation medium 6 (with a high damage threshold, weak terahertz wave absorption, pronounced nonlinear effects) and input conditions variation, e.g., changing pump radiation parameters or modifying the experimental scheme configuration. The former includes the research on the generation of terahertz waves in a wide variety of gases 7 , metals 8 , as well as relatively new works on liquid media [9][10][11] . As an example, for input conditions variation, it was shown that the terahertz wave pulse energy could be more than 5fold enhanced by applying the abruptly autofocusing beam instead of the usual Gaussian one under the same conditions 12 .…”

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confidence: 99%

Varying pre-plasma properties to boost terahertz wave generation in liquids

et al. 2021

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Laser-driven nonlinear phenomena can both reveal the structural features of materials and become the basis for the development of various translated technologies, including highly intense terahertz sources. Here we realize a modified single-color double-pulse excitation scheme for enhancing the terahertz wave generation in flat liquid jets, and we show that the pre-ionization effect is crucial for finding the optimal input conditions. The experimental results, being supported by numerical simulations, reveal the preference for longer pre-pulses to induce the effective ionization process and shorter signals for the strong laser-plasma interaction. In addition to the identified features of the terahertz wave energy enhancement with respect to the duration change for both pulses and their ratio variation, we state the possibility of achieving the optical-to-THz conversion efficiency value up to 0.1% in the case of double-pulse excitation of an α-pinene jet.

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“…Dey et al reported THz wave generation from ionized liquids by focusing intense laser into a cuvette [11]. With successive studies [12][13][14][15][49][50][51], THz wave generation from liquids shows different properties comparing to that from other targets. In this paper, we review recent studies of THz wave generation from flowing liquid targets as well as the ultrafast dynamics of liquids under intense THz excitation.…”

Section: Introductionmentioning

confidence: 99%

Broadband THz Sources from Gases to Liquids

et al. 2021

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Matters are generally classified within four states: solid, liquid, gas, and plasma. Three of the four states of matter (solid, gas, and plasma) have been used for THz wave generation with short laser pulse excitation for decades, including the recent vigorous development of THz photonics in gases (air plasma). However, the demonstration of THz generation from liquids was conspicuously absent. It is well known that water, the most common liquid, is a strong absorber in the far infrared range. Therefore, liquid water has historically been sworn off as a source for THz radiation. Recently, broadband THz wave generation from a flowing liquid target has been experimentally demonstrated through laser-induced microplasma. The liquid target as the THz source presents unique properties. Specifically, liquids have the comparable material density to that of solids, meaning that laser pulses over a certain area will interact with three orders more molecules than an equivalent cross-section of gases. In contrast with solid targets, the fluidity of liquid allows every laser pulse to interact with a fresh area on the target, meaning that material damage or degradation is not an issue with the high-repetition rate intense laser pulses. These make liquids very promising candidates for the investigation of high-energy-density plasma, as well as the possibility of being the next generation of THz sources.

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Preference of subpicosecond laser pulses for terahertz wave generation from liquids

Cited by 37 publications

References 57 publications

Generation and manipulation of chiral terahertz waves in the three-dimensional topological insulator Bi2Te3

Generation and manipulation of chiral terahertz waves in the three-dimensional topological insulator Bi2Te3

Varying pre-plasma properties to boost terahertz wave generation in liquids

Broadband THz Sources from Gases to Liquids

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