Enhancement of THz generation by feedback-optimized wavefront manipulation

Hah, Jungmoo; Jiang, Wenying; He, Zhaohan; Nees, J.; Hou, Bixue; Thomas, Alexander; Krushelnick, K.

doi:10.1364/oe.25.017271

Cited by 12 publications

(7 citation statements)

References 30 publications

(45 reference statements)

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“…Laser excitation with chirped pulses [20] or two-colors [16,[20][21][22][23] has been carried out with discussions mainly via the four-wave mixing or ponderomotive force mechanism. Furthermore, a feedback method of laser wave-front manipulation can control THz wave emission [24]. One disadvantage of gaseous targets is low absorption cross section at the incident laser wavelength.…”

Section: Introductionmentioning

confidence: 99%

Giant Enhancement of THz Wave Emission under Double-Pulse Excitation of Thin Water Flow

et al. 2020

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Simultaneous measurements of THz wave and hard X-ray emission from thin and flat water flow when irradiated by double femtosecond laser pulses (800 nm, 35 fs, transform-limited, 0.5 kHz, delay times up to 15 ns) were carried out at the transmission and the reflection sides of the flow with THz time-domain spectroscopy and Geiger counters. THz wave emission spectra show their dynamic peak-shifts toward the low frequency with the highest intensity enhancements more than 1.5 × 10 3 times in |E| 2 at the delay time of 4.7 ns between the two pulses, while X-ray intensity enhancements are limited to about 20 times at 0 ns under the same experimental conditions. The mechanisms for the spectral changes and the intensity enhancements in THz wave emission are discussed from the viewpoint of laser ablation on the water flow induced by the pre-pulse irradiation.

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Section: Introductionmentioning

confidence: 99%

Giant Enhancement of THz Wave Emission under Double-Pulse Excitation of Thin Water Flow

et al. 2020

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“…Going to shorter wavelength allows for the direct use of highly developed ultrafast ytterbium lasers, which are able to deliver a power in excess of 10 kW [20]. The efficiency of the generation process at this wavelength is still comparable to that achieved in GaP and LiNbO 3 [21][22][23]. In a previous publication [6] we demonstrated the generation of 50 mW average power with an efficiency of 4 • 10 −4 .…”

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confidence: 84%

Gas-plasma-based generation of broadband terahertz radiation with 640 mW average power

et al. 2021

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We present a high-power source of broadband terahertz radiation covering the whole THz spectral region (0.1 − 30 THz). The two-color gas plasma generation process is driven by a state-of-the-art Ytterbium fiber chirped pulse amplification system based on coherent combination of 16 rod-type amplifiers. Prior to the THz generation, the pulses are spectrally broadened in a multipass-cell and compressed to 37 fs with a pulse-energy of 1.3 mJ at a repetition rate of 500 kHz. A gas-jet scheme has been employed for the THz generation, increasing the efficiency of the process to 0.1%. The air-biasedcoherent-detection scheme is implemented to characterize the full bandwidth of the generated radiation. A THz average power of 640 mW is generated, which is the highest THz average power achieved to date. This makes this source suitable for a variety of applications, e.g. spectroscopy of strongly absorbing samples or driving nonlinear effects for the studies of material properties.

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“…The electron beam charge, energy spectra and beam pointing have been optimized. The combination of genetic algorithm and DM has been applied to other high-power laser experiments as well [ 215 – 219 ] .Streeter et al [ 220 ] used a similar technique to optimize ultra-fast heating of atomic clusters at joule-level energies, but instead of controlling the spatial wavefront, they controlled the spectral phase up to its fourth order. The genetic algorithm was based on a population of 15 individuals and children generations were evaluated.…”

Section: Optimizationmentioning

confidence: 99%

Data-driven science and machine learning methods in laser–plasma physics

Döpp

Eberle

Howard

et al. 2023

High Pow Laser Sci Eng

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Laser-plasma physics has developed rapidly over the past few decades as lasers have become both more powerful and more widely available. Early experimental and numerical research in this field was dominated by single-shot experiments with limited parameter exploration. However, recent technological improvements make it possible to gather data for hundreds or thousands of different settings in both experiments and simulations. This has sparked interest in using advanced techniques from mathematics, statistics and computer science to deal with, and benefit from, big data. At the same time, sophisticated modeling techniques also provide new ways for researchers to deal effectively with situation where still only sparse data are available. This paper aims to present an overview of relevant machine learning methods with focus on applicability to laser-plasma physics and its important sub-fields of laser-plasma acceleration and inertial confinement fusion.

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Enhancement of THz generation by feedback-optimized wavefront manipulation

Cited by 12 publications

References 30 publications

Giant Enhancement of THz Wave Emission under Double-Pulse Excitation of Thin Water Flow

Giant Enhancement of THz Wave Emission under Double-Pulse Excitation of Thin Water Flow

Gas-plasma-based generation of broadband terahertz radiation with 640 mW average power

Data-driven science and machine learning methods in laser–plasma physics

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