Multimode dynamics in a short-pulse THz free electron laser

Chulkov, R. V.; Goryashko, Vitaliy; Arslanov, Denis; Jongma, Rienk T.; Zande, Wim J. van der; Zhaunerchyk, Vitali

doi:10.1103/physrevstab.17.050703

Cited by 9 publications

(10 citation statements)

References 29 publications

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“…FEL lasers have some advantageous characteristics, e.g., a high average power and high peak power (e.g., refs − ), pulse durations from quasi continuous to sub-picosecond range (e.g., refs , ), repetition rates up into the kHz region (e.g., ref ). A typical frequency region can start around 10 cm –1 (e.g., ref ) up to typically about 2000 cm –1 , and with much lower intensity partly also in the IR region up to about 3300 cm –1 (e.g., ref ); in some FEL facilities, the spectral range is further extended via the far-IR region down to the THz region (e.g., ref ). The far-IR region below approximately 800 cm –1 still remains the domain of the FEL lasers, because this region cannot sufficiently be covered by table top lasers (see below).…”

Section: Introduction To Experimental Methodsmentioning

confidence: 99%

Neutral Peptides in the Gas Phase: Conformation and Aggregation Issues

et al. 2020

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Combined IR and UV laser spectroscopic techniques in molecular beams merged with theoretical approaches have proven to be an ideal tool to elucidate intrinsic structural properties on a molecular level. It offers the possibility to analyze structural changes by successively adding aggregation partners and thus an environment to a molecule. By this, it further makes these techniques a valuable starting point for a bottom-up approach in understanding the forces shaping larger molecular systems. This bottomup approach was successfully applied to neutral amino acids starting around the 1990s. Ever since experimental and theoretical methods developed further and investigations could be extended to larger peptide systems. Beyond, the review gives an introduction to secondary structures and experimental methods as well as a summary on theoretical approaches. Vibrational frequencies being characteristic probes of molecular structure and interactions are especially addressed. Archetypal biologically relevant secondary structures investigated by molecular beam spectroscopy are described and the influences of specific peptide residues on conformational preferences as well as the competition between secondary structures are discussed. Important influences like microsolvation or aggregation behaviour are presented. Beyond the linear α-peptides the main results of structural analysis on cyclic systems as well as on β-and γ-peptides are summarized. Overall, this contribution addresses current aspects of molecular beam spectroscopy on peptides and related species and provides molecular level insights into manifold issues of chemical and biochemical relevance. 45) , non-protected (cf. e.g. 46-48) and protected amino acids (cf. e.g. 49) up to dipeptide models (cf. e.g. 50).In this context, laser spectroscopic techniques combining IR and UV excitations, that one can consider as belonging to the so-called 'action spectroscopies', provide an isomer-selective method of choice to tackle the 87 ) or immunoglobulins (cf. e.g. 88), but they are also found in context with neurodegenerative diseases (cf. e.g. [89][90][91][92][93][94][95] and Section 12). A further structure associated with these diseases (cf. e.g. 96 ) is the β-helix, which presents a protein structure of several parallel β-strands in a helical arrangement with a frequently repetitive amino acid sequence. The structure is stabilized by H-bonds, sometimes ionic interactions or so called protein-protein interactions, which e.g. include electrostatic and hydrophobic effects. Further aspects of peptide structure in gas phase The role of protection groupsWith the unmodified N-and C-terminus amino acids and peptides can exhibit strong preferences for intramolecular H-bonds involving the N-and C-terminus, and can also form intermolecular H-bonds leading to polymer chains. Nevertheless, in a context where the description of the properties of a protein or a long peptide (with respect to its backbone) by smaller peptides is targeted, the introduction of protecting groups at the N-and...

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Section: Introduction To Experimental Methodsmentioning

confidence: 99%

Neutral Peptides in the Gas Phase: Conformation and Aggregation Issues

et al. 2020

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“…But this is not compatible with midinfrared lasing, which requires free propagation and spherical mirrors. Moreover in this configuration, recent results show that many power gaps do also appear in the far infrared [11]. As shown recently [12], this effect is different and comes from the competition between the high and low frequency branches of the resonant FEL condition that exist in a planar waveguide [13].…”

Section: Discussionmentioning

confidence: 64%

Evidence for competition modes in a partially guided far-infrared free-electron laser

Ortéga

Berthet

Glotin

et al. 2014

Phys. Rev. ST Accel. Beams

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The infrared free-electron laser (FEL) offers a large tunability since the FEL gain remains high throughout the infrared spectral range, and the reflectivity of metal mirrors remains also close to unity. The main limitation comes from the diffraction of the optical beam due to the finite size of the vacuum chamber of the undulator. A solution is to use this chamber as a waveguide by adapting the radius of curvature of the cavity mirrors to this regime. Then, as has been shown before, a minimum appears in the spectrum that can be produced by the FEL. We discuss the physical mechanism of this particular regime and compare it to experiments using vacuum chambers of different transverse sizes. A good agreement is found with results of simulations and with a simple analytical formula.

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“…The FIR oscillator is driven by the same Linac as MIR-FEL so that the electron beam quality is almost the same but a little worse. However, as the required electron beam energy is lower (15)(16)(17)(18)(19)(20)(21)(22)(23)(24)(25), the energy spread can be reduced to smaller than 150 keV. We may need to decompress the microbunch to suppress the slippage effect for long wavelength.…”

Section: Fir Oscillatormentioning

confidence: 99%

Design of FELiChEM, the first infrared free-electron laser user facility in China

Jia

Zhang

et al. 2017

Chinese Phys. C

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FELiChEM is a new experimental facility under construction at University of Science and Technology of China (USTC), whose core device is two free electron laser oscillators generating middle-infrared and far-infrared laser and covering the spectral range of 2.5-200 µm. It will be a dedicated infrared light source aiming at energy chemistry research. We present the brief design of FEL oscillators with the emphasis put on the middle-infrared oscillator. Most of the basic parameters are determined and the anticipated performance of the output radiation is given. The first light of FELiChEM is targeted for the end of 2017.

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Multimode dynamics in a short-pulse THz free electron laser

Cited by 9 publications

References 29 publications

Neutral Peptides in the Gas Phase: Conformation and Aggregation Issues

Neutral Peptides in the Gas Phase: Conformation and Aggregation Issues

Evidence for competition modes in a partially guided far-infrared free-electron laser

Design of FELiChEM, the first infrared free-electron laser user facility in China

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