Quasi-phase-matching and quantum-path control of high-harmonic generation using counterpropagating light

Zhang, Xiaoshi; Lytle, Amy L.; Popmintchev, Tenio; Zhou, Xibin; Kapteyn, Henry C.; Murnane, Margaret M.; Cohen, Oren

doi:10.1038/nphys541

Cited by 222 publications

(143 citation statements)

References 23 publications

Supporting

Mentioning

138

Contrasting

Order By: Relevance

“…Differently from QPM in periodically-poled nonlinear crystals [13], where the sign of the nonlinear coefficient is periodically flipped so as to always add constructively interfering contributes to the generated field, QPM in HHG has so far been demonstrated by periodically switchingoff harmonic generation during the out-of-phase intervals. Either a modulation of the pump laser intensity in a modulated-diameter, hollow-core, gas-filled waveguide [14,15,16], or the use of a counter-propagating train of pulses [17,18] were used at this purpose. Recently, theoretical studies have predicted the possibility of achieving QPM by periodically modulating the density of the gas medium [19,20], and a proof-of-concept work has shown the coherent buildup of the harmonic field in two separated gas sources [21].…”

mentioning

confidence: 99%

Enhancing the yield of high-order harmonics with an array of gas jets

2008

View full text Add to dashboard Cite

We report the experimental observation of an enhancement in the yield of high-order harmonics using an array of gas jets as the source medium. By comparing the experimental outcome for jet arrays of different spacings with the predicted harmonic intensity in the case of slit sources of equivalent lengths, we clearly show how the periodic modulation of the gas density can improve the harmonic yield. This behavior may attributed to a quasi-phase-matching effect which increases the length of coherent harmonic build-up during propagation by partially counteracting the dephasing induced by free electrons.PACS numbers: 32.80. Rm,42.65.Ky,32.80.Fb Keywords: Since its discovery in 1987 [1], the phenomenon of highorder harmonic generation (HHG) has become one of the most interesting topics in the field of highly nonlinear processes. Apart from its fundamental physics interest, HHG is now one of the most promising ways to obtain tunable, short-pulse, narrow-band radiation in the vacuum and extreme ultraviolet (VUV and XUV), and in the soft X-ray regions, where other coherent sources are scarcely available. However, the possibility of using high-order harmonics as a table-top VUV-XUV coherent source for applications is strongly connected to the optimization of the brightness of the source over the broadest spectral range.As in many other nonlinear processes, conversion efficiency in HHG depends on the interplay between the single-atom response [2] and the macroscopic response during propagation in the medium [3]. In particular, a constructive interference of the harmonic field emitted from different locations of the source length can only be obtained over the so-called coherence length L c . For media longer than L c , destructive interference soon depletes the generated field and dramatically limits the conversion efficiency. By an appropriate choice of the interaction parameters it is often possible to make the coherence length longer than the medium, thus reaching the so-called phase-matching conditions. However, when phase-matching is not achievable, one can still artificially beat the coherence length limits by properly modulating the interaction parameters along the field propagation direction. Examples of such quasi-phase-matching (QPM) techniques now abound for low-order nonlinear phenomena in structured crystals, and a few examples have been recently demonstrated in HHG. Many different phenomena contribute to limit the coherence length in HHG. Here, the atomic dispersion and the geometric Guoy phase [4,5], are always accompanied by the dispersion connected to free electrons in the partially ionized medium [6,7], and by the characteristic atomic dipole phase [8,9,10,11,12]. Depending on the gas type and density, and on the level of ionization, the coherence length in HHG is usually so short as to pose a serious limit to significant conversion efficiencies. Differently from QPM in periodically-poled nonlinear crystals [13], where the sign of the nonlinear coefficient is periodically flipped so as to always add c...

show abstract

mentioning

confidence: 99%

Enhancing the yield of high-order harmonics with an array of gas jets

2008

View full text Add to dashboard Cite

show abstract

“…Here we propose a new class of QPM techniques by controlling the polarization in an optical waveguide by either: (i) rotating the polarization of the driving field [1,2] in a circularly birefringent waveguide; or (ii) modulating the ellipticity of the driver polarization [3,4] in a linearly birefringent system. The key advantage of this new class of polarization-controlled QPM is its simplicity compared to other QPM techniques since it avoids the need for additional laser pulses [5] or longitudinally-structured waveguides [6]. Instead, the only requirement is a waveguide with a suitable value of birefringence.…”

Section: Introductionmentioning

confidence: 99%

Polarization-controlled quasi-phase-matching of high harmonic generation

Liu

O’Keeffe

Hooker

2013

EPJ Web of Conferences

View full text Add to dashboard Cite

show abstract

“…There are many lower peaks besides the main one, owing to phase mismatching of the harmonics. However, many ways are available to modulate the phases between harmonics, such as, chirp compensation, [6] grating-assisted phase matching, [26] etc. The solid line in Fig.…”

Section: -3mentioning

confidence: 99%

Controls for the generation of high-order harmonics and attosecond pulses by an infrared laser field combined with a low-frequency pulse

He¹,

Guo²,

2012

Chinese Phys. B

View full text Add to dashboard Cite

We investigate high-order harmonic generations by controlling various quantum paths of harmonics in an infrared laser field which combines a low-frequency pulse. Both classical theory and the quantum wavelet transform method are used to understand the physics of harmonics. By adjusting the carrier envelope phase of the fundamental field, the intensities of harmonic spectra increase and the harmonics in the plateau become regular. Attosecond pulses each with a duration of 58 as are obtained directly by compressing the harmonics, and with phase compensation an isolated attosecond pulse less than 30 as can be generated.

show abstract

Quasi-phase-matching and quantum-path control of high-harmonic generation using counterpropagating light

Cited by 222 publications

References 23 publications

Enhancing the yield of high-order harmonics with an array of gas jets

Enhancing the yield of high-order harmonics with an array of gas jets

Polarization-controlled quasi-phase-matching of high harmonic generation

Controls for the generation of high-order harmonics and attosecond pulses by an infrared laser field combined with a low-frequency pulse

Contact Info

Product

Resources

About