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High harmonic generation

About: High harmonic generation is a research topic. Over the lifetime, 11694 publications have been published within this topic receiving 222650 citations. The topic is also known as: HHG.


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Patent
11 Jul 2001
TL;DR: A Q-switched, diode-pumped, solid-state (DPSS) laser employs harmonic generation through nonlinear crystals (72) to generate UV light for both link processing and target alignment as mentioned in this paper.
Abstract: A Q-switched, diode-pumped, solid-state (DPSS) laser (54) employs harmonic generation through nonlinear crystals (72) to generate UV light (74) for both link processing and target alignment The type and geometry of the nonlinear crystals (72) are selected, and their temperatures are precisely controlled, to produce focused spot sizes with excellent beam quality for severing of IC fuses A fraction of the laser output (56) can be utilized in a secondary target alignment system (50) An imaging optics module (52) may be employed to further enhance the shape quality of either or both of the secondary and primary beams Each beam passes through a detection module (100) that measures the incident and reflected light The two beams pass through a common combiner to facilitate calibration and alignment of the beams and subsequent link processing

125 citations

Journal ArticleDOI
TL;DR: It is found that considerable resonant excitation occurs by laser induced electron transfer to neighboring ions and multiple frequency (fractional-order) harmonics are observed from the excited states shifted by some energy Δ from the main Nω energy harmonics.
Abstract: Multichannel molecular high-order harmonic generation (MHOHG) from a single electron asymmetric molecular ion ${\mathrm{HeH}}^{2+}$ is investigated numerically. It is found that considerable resonant excitation occurs by laser induced electron transfer (LIET) to neighboring ions and multiple frequency (fractional-order) harmonics are observed from the excited states shifted by some energy $\ensuremath{\Delta}$ from the main $N\ensuremath{\omega}$ energy harmonics. A time series analysis is used to confirm this MHOHG channel which is created by initial ionization from the excited state prepared by LIET and recombination to the neighboring ion at specific field phases, resulting in interference between recombination pathways from ground and excited states.

124 citations

Journal ArticleDOI
TL;DR: In this paper, the authors report ultra-strong high-order nonlinear multiphoton processes in monolayer MoS$_2$ (1L-MoS$-2$) with a continuum-model Hamiltonian and quantum-mechanical diagrammatic perturbation theory.
Abstract: We report ultra-strong high-order nonlinear multiphoton processes in monolayer MoS$_2$ (1L-MoS$_2$): the third harmonic is thirty times stronger than the second harmonic, and the fourth harmonic is comparable to the second harmonic. We find that second and third harmonic processes are strongly dependent on elliptical polarization, which can be used to selectively tune harmonic generation with different orders. We explain this by calculating the nonlinear response functions of 1L-MoS$_2$ with a continuum-model Hamiltonian and quantum-mechanical diagrammatic perturbation theory, highlighting the crucial role of trigonal warping. A similar effect is expected for all other transition-metal dichalcogenides. Our results pave the way for efficient and tunable harmonic generation based on layered materials for various applications, including microscopy and imaging

124 citations

Journal ArticleDOI
TL;DR: In this paper, the authors developed a density-matrix formalism in the length gauge to calculate the nonlinear response of intrinsic monolayer graphene at terahertz frequencies and found that the interplay of the interband and intraband dynamics leads to strong harmonic generation at moderate field amplitudes.
Abstract: We develop a density-matrix formalism in the length gauge to calculate the nonlinear response of intrinsic monolayer graphene at terahertz frequencies. Employing a tight-binding model, we find that the interplay of the interband and intraband dynamics leads to strong harmonic generation at moderate field amplitudes. In particular, we find that at low temperature, the reflected field of undoped suspended graphene exhibits a third harmonic amplitude that is 32% of the fundamental for an incident field of 100 V/cm. Moreover, we find that up to the seventh harmonic and beyond are generated.

124 citations

Journal ArticleDOI
TL;DR: In this article, the femto and picosecond pulses delivered by the amplifier are coupled into two different photonic crystal fibers and obtained the highest output power of 5 W with a spectrum ranging from below 500 nm up to above 1800 nm.

124 citations


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Performance
Metrics
No. of papers in the topic in previous years
YearPapers
2023177
2022438
2021399
2020489
2019516
2018433