Water window attosecond sources generation by using the multi-cycle time-delay two circularly polarized pulses

2015 ◽  
Vol 29 (23) ◽  
pp. 1550170 ◽  
Author(s):  
Li-Qiang Feng ◽  
Hang Liu
Keyword(s):  
Time Delay ◽  
Cycle Time ◽  
Delay Time ◽  
Harmonic Spectrum ◽  
High Order ◽  
Circularly Polarized ◽  
Water Window ◽  
Attosecond Pulses ◽  
Window Region ◽  
Whole Water

In this paper, a promising scheme is proposed to generate the water window isolated attosecond pulses from the high-order harmonics by using the multi-cycle time-delay two circularly polarized pulses. The results show that with the introduction of delay time of the two pulses, not only the harmonic cutoff is extended, but also the modulation on the harmonic spectrum is suppressed. Especially for the [Formula: see text] nm, [Formula: see text] nm and the [Formula: see text] nm two cases, a 341 eV and a 502 eV supercontinua including the whole water window region are obtained. Finally, by properly superposing the harmonics in the supercontinua regions, a series of sub-34as wavelength-tunable attosecond pulses in the water window region can be obtained.

scholarly journals Control of the polarization direction of isolated attosecond pulses using inhomogeneous two-color fields

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Stephen Maina Njoroge ◽  
Hua Yuan ◽  
Kinyua Dickson ◽  
Qingbin Zhang ◽  
Pengfei Lan
Keyword(s):  
Polarization Direction ◽  
Relative Angle ◽  
Water Window ◽  
High Order Harmonic ◽  
Fundamental Pulse ◽  
Wide Range ◽  
Attosecond Pulses ◽  
Linearly Polarized ◽  
Window Region ◽  
And Control

AbstractWe theoretically demonstrate the control of the polarization direction of isolated attosecond pulses (IAPs) with inhomogeneous two-color fields synthesized by an 800-nm fundamental pulse and a 2000-nm control pulse having crossed linear polarizations. The results show that by using the temporally and spatially shaped field, the high-order harmonic generation (HHG) process can be efficiently controlled. An ultra-broad supercontinuum ranging from 150th to 400th harmonics which covers the water window region is generated. Such a supercontinuum supports the generation of a 64-as linearly polarized IAP, whose polarization direction is at about 45° with respect to the x axis. Moreover, we analyze the influence of the inhomogeneity parameters and the relative angle of the fundamental and control pulses on the IAP generation. It is shown that the polarization direction of the IAP can rotate in a wide range approximately from 8° to 90° relative to the x axis when the inhomogeneity parameters and the relative angle vary.

Initial state effect on waveform control of high-order harmonic spectrum and attosecond pulse generation

2021 ◽  
pp. 2150366
Author(s):  
Hang Liu ◽  
Xiaodan Jing ◽  
Yan Qiao ◽  
John McCain ◽  
Liqiang Feng
Keyword(s):  
Harmonic Spectrum ◽  
Pulse Generation ◽  
Attosecond Pulse ◽  
High Order ◽  
High Order Harmonic Generation ◽  
Initial State ◽  
High Order Harmonic ◽  
Waveform Control ◽  
Attosecond Pulses ◽  
Attosecond Pulse Generation

In this paper, the waveform control of high-order harmonic generation and attosecond pulse generation from a different initial state of He atom has been investigated. The results show that (i) by properly controlling the carrier-envelope phases, the time delays and the laser intensities of a 3-color laser pulse, the best waveforms for the harmonic cut-off extension can be found. Although the harmonic cut-offs from the ground initial state and the superposition initial state are almost the same, the harmonic intensities from the superposition initial state are 4 to 5 orders of magnitudes higher than those from the ground initial state. (ii) With the introduction of the inhomogeneous effect, the harmonic cut-offs can be further extended. However, the harmonic intensities from the superposition initial state are remarkably decreased compared with those from the homogeneous pulses, which is unbeneficial to generate the intense attosecond pulses. (iii) When the ground state is chosen to be the initial and with the assistance of the 4th UV pulse, not only the larger harmonic cut-offs can be obtained, but also the stronger harmonic plateaus can be found, which is favorable for producing the intense attosecond pulses. Thus, at the end of this paper, by superposing the harmonics from the best harmonic spectra, the single attosecond pulses with the duration of 36 as can be obtained.

scholarly journals EVALUASI PRODUKTIVITAS ALAT GALI MUAT DAN ALAT ANGKUT PADA PEMINDAHAN OVERBURDEN PIT 10 DI PT BERKAT TAMBANG SEJAHTERA, KECAMATAN LOKPAIKAT, KABUPATEN TAPIN, PROVINSI KALIMANTAN SELATAN

2021 ◽  
Vol 6 (1) ◽  
pp. 33
Author(s):  
Agung Yulianto ◽  
Eko Santoso ◽  
Karina Shella Putri
Keyword(s):  
Time Delay ◽  
Cycle Time ◽  
Delay Time ◽  
Dump Truck

PT Berkat Tambang Sejahtera memiliki target produktivitas overburden yang telah ditentukan yaitu sebesar 200 BCM/jam. Tidak tercapainya target perusahaan sehingga perlu adanya analisis terhadap faktor-faktor yang mempengaruhi produktivitas alat gali muat dan alat angkut di lapangan antara lain waktu siklus kerja dan waktu hambatan kerja.Penelitian ini dilakukan dengan menganalisis faktor-faktor pendukung produktivitas seperti cycle time, delay time dan geometri jalan, sehingga dapat dilakukan upaya peningkatan produktivitas agar target perusahaan dapat tercapai.Pada hasil penelitian didapatkan rata-rata produktivitas aktual Hitachi ZX470LC-5G sebesar 175 BCM/jam dan jumlah alat angkut sebanyak 6 unit didapatkan rata-rata total produktivitas aktual Hino 500 FM260JD sebesar 173,44 BCM/Jam. Upaya yang dilakukan agar target tercapai yaitu dengan melakukan simulasi perbaikan cycle time dilakukan dengan cara peningkatan kecepatan dump truck Hino 500 FM260JD pada waktu bermuatan sebesar 23 km/jam dan pada saat kosongan 28 km/jam. Perbaikan yang dapat dilakukan agar kecepatan tempuh yang ditargetkan dapat terpenuhi yaitu dengan memperhatikan kondisi jalan angkut yang dilalui pada saat muatan berisi ataupun muatan kosong. Dalam penelitian ini rekomendasi yang diberikan berupa perbaikan geometri jalan angkut seperti lebar jalan dan grade jalan. Kata kunci: produktivitas, cycle time, delay time, geometri jalan

Improvement of High-Order Harmonic Generation Via Controlling Multiple Acceleration–Recombination Process

2019 ◽  
Vol 74 (7) ◽  
pp. 561-571 ◽  
Author(s):  
Yi Li ◽  
Li-Qiang Feng ◽  
Yan Qiao
Keyword(s):  
Harmonic Generation ◽  
Laser Field ◽  
High Order ◽  
Recombination Process ◽  
Half Cycle ◽  
High Order Harmonic Generation ◽  
Water Window ◽  
High Order Harmonic ◽  
Window Region ◽  
Frequency Chirping

AbstractThe multiple acceleration–recombination process in high-order harmonic generation (HHG) has been investigated and discussed. Generally, the HHG can be explained through the ionization–acceleration–recombination process in each half-cycle waveform of the laser field. In this article, through the waveform control via the two-colour frequency-chirping laser field, the multiple acceleration–recombination process of the free electron in a specific “W” waveform structure can be found, which will lead to the larger emitted photon energies. Moreover, with the optimization of this “W” waveform by changing the frequency chirps, the carrier envelope phases, and the delay time, not only the efficiency of HHG can be enhanced compared with that from the original chirp-free pulse, but also the larger harmonic cutoff can be obtained. Further, with the assistance of the unipolar pulses, the cutoff and the efficiency of HHG can be further improved, showing a water window spectral continuum with the intensity enhancement of 66 times. As a result, by properly superposing some selected harmonics on the spectral continuum, three intense 38-as pulses in the water window region can be obtained.

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