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Route to optimal generation of soft X-ray high harmonics with synthesized two-color laser pulses.

Jin C, Wang G, Le AT, Lin CD - Sci Rep (2014)

Bottom Line: Here we show that the conversion efficiency may be drastically increased with an optimized two-color pulse.By employing an optimally synthesized 2-µm mid-infrared laser and a small amount of its third harmonic, we show that harmonic yields from sub- to few-keV energy can be increased typically by ten-fold over the optimized single-color one.By combining with favorable phase-matching and together with the emerging high-repetition MHz mid-infrared lasers, we anticipate efficiency of harmonic yields can be increased by four to five orders in the near future, thus paving the way for employing high harmonics as useful broadband tabletop light sources from the extreme ultraviolet to the X-rays, as well as providing new tools for interrogating ultrafast dynamics of matter at attosecond timescales.

View Article: PubMed Central - PubMed

Affiliation: J. R. Macdonald Laboratory, Department of Physics, Kansas State University, Manhattan, Kansas 66506, USA.

ABSTRACT
High harmonics extending to X-rays have been generated from gases by intense lasers. To establish these coherent broadband radiations as an all-purpose tabletop light source for general applications in science and technology, new methods are needed to overcome the present low conversion efficiencies. Here we show that the conversion efficiency may be drastically increased with an optimized two-color pulse. By employing an optimally synthesized 2-µm mid-infrared laser and a small amount of its third harmonic, we show that harmonic yields from sub- to few-keV energy can be increased typically by ten-fold over the optimized single-color one. By combining with favorable phase-matching and together with the emerging high-repetition MHz mid-infrared lasers, we anticipate efficiency of harmonic yields can be increased by four to five orders in the near future, thus paving the way for employing high harmonics as useful broadband tabletop light sources from the extreme ultraviolet to the X-rays, as well as providing new tools for interrogating ultrafast dynamics of matter at attosecond timescales.

No MeSH data available.


Related in: MedlinePlus

Minimum fundamental wavelength for generating maximal harmonic yields versus the cutoff energy using Ar, Ne and He targets, for optimized waveform (WF) and single-color (SC) pulses.Waveform is synthesized by the fundamental laser and its 3rd harmonic. The ionization level in the simulation is set at 2% level. Other constraints in the optimization are discussed in the text.
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f1: Minimum fundamental wavelength for generating maximal harmonic yields versus the cutoff energy using Ar, Ne and He targets, for optimized waveform (WF) and single-color (SC) pulses.Waveform is synthesized by the fundamental laser and its 3rd harmonic. The ionization level in the simulation is set at 2% level. Other constraints in the optimization are discussed in the text.

Mentions: Figure 1 summarizes the main results of our simulations for cutoff energies from 0.2 to 1 keV. It shows the minimum (also the optimal) fundamental wavelength that can be used to generate maximal harmonic yields versus the desired cutoff energy for the three targets of Ar, Ne and He, respectively. While it is always possible to use longer wavelength to achieve the same cutoff energy, the harmonic yields reached would be weaker. The results are compared to the optimal single-color driving lasers. In both cases the degree of ionization is set at the same 2% level.


Route to optimal generation of soft X-ray high harmonics with synthesized two-color laser pulses.

Jin C, Wang G, Le AT, Lin CD - Sci Rep (2014)

Minimum fundamental wavelength for generating maximal harmonic yields versus the cutoff energy using Ar, Ne and He targets, for optimized waveform (WF) and single-color (SC) pulses.Waveform is synthesized by the fundamental laser and its 3rd harmonic. The ionization level in the simulation is set at 2% level. Other constraints in the optimization are discussed in the text.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4233338&req=5

f1: Minimum fundamental wavelength for generating maximal harmonic yields versus the cutoff energy using Ar, Ne and He targets, for optimized waveform (WF) and single-color (SC) pulses.Waveform is synthesized by the fundamental laser and its 3rd harmonic. The ionization level in the simulation is set at 2% level. Other constraints in the optimization are discussed in the text.
Mentions: Figure 1 summarizes the main results of our simulations for cutoff energies from 0.2 to 1 keV. It shows the minimum (also the optimal) fundamental wavelength that can be used to generate maximal harmonic yields versus the desired cutoff energy for the three targets of Ar, Ne and He, respectively. While it is always possible to use longer wavelength to achieve the same cutoff energy, the harmonic yields reached would be weaker. The results are compared to the optimal single-color driving lasers. In both cases the degree of ionization is set at the same 2% level.

Bottom Line: Here we show that the conversion efficiency may be drastically increased with an optimized two-color pulse.By employing an optimally synthesized 2-µm mid-infrared laser and a small amount of its third harmonic, we show that harmonic yields from sub- to few-keV energy can be increased typically by ten-fold over the optimized single-color one.By combining with favorable phase-matching and together with the emerging high-repetition MHz mid-infrared lasers, we anticipate efficiency of harmonic yields can be increased by four to five orders in the near future, thus paving the way for employing high harmonics as useful broadband tabletop light sources from the extreme ultraviolet to the X-rays, as well as providing new tools for interrogating ultrafast dynamics of matter at attosecond timescales.

View Article: PubMed Central - PubMed

Affiliation: J. R. Macdonald Laboratory, Department of Physics, Kansas State University, Manhattan, Kansas 66506, USA.

ABSTRACT
High harmonics extending to X-rays have been generated from gases by intense lasers. To establish these coherent broadband radiations as an all-purpose tabletop light source for general applications in science and technology, new methods are needed to overcome the present low conversion efficiencies. Here we show that the conversion efficiency may be drastically increased with an optimized two-color pulse. By employing an optimally synthesized 2-µm mid-infrared laser and a small amount of its third harmonic, we show that harmonic yields from sub- to few-keV energy can be increased typically by ten-fold over the optimized single-color one. By combining with favorable phase-matching and together with the emerging high-repetition MHz mid-infrared lasers, we anticipate efficiency of harmonic yields can be increased by four to five orders in the near future, thus paving the way for employing high harmonics as useful broadband tabletop light sources from the extreme ultraviolet to the X-rays, as well as providing new tools for interrogating ultrafast dynamics of matter at attosecond timescales.

No MeSH data available.


Related in: MedlinePlus