Sub-50-as isolated extreme ultraviolet continua generated by 1.6-cycle near-infrared pulse combined with double optical gating scheme

2018 ◽  
Vol 112 (18) ◽  
pp. 181105 ◽  
Author(s):  
Katsuya Oguri ◽  
Hiroki Mashiko ◽  
Tatsuya Ogawa ◽  
Yasutaka Hanada ◽  
Hidetoshi Nakano ◽  
...  
2021 ◽  
Vol 127 (4) ◽  
Author(s):  
S. Skruszewicz ◽  
S. Fuchs ◽  
J. J. Abel ◽  
J. Nathanael ◽  
J. Reinhard ◽  
...  

AbstractWe present an overview of recent results on optical coherence tomography with the use of extreme ultraviolet and soft X-ray radiation (XCT). XCT is a cross-sectional imaging method that has emerged as a derivative of optical coherence tomography (OCT). In contrast to OCT, which typically uses near-infrared light, XCT utilizes broad bandwidth extreme ultraviolet (XUV) and soft X-ray (SXR) radiation (Fuchs et al in Sci Rep 6:20658, 2016). As in OCT, XCT’s axial resolution only scales with the coherence length of the light source. Thus, an axial resolution down to the nanometer range can be achieved. This is an improvement of up to three orders of magnitude in comparison to OCT. XCT measures the reflected spectrum in a common-path interferometric setup to retrieve the axial structure of nanometer-sized samples. The technique has been demonstrated with broad bandwidth XUV/SXR radiation from synchrotron facilities and recently with compact laboratory-based laser-driven sources. Axial resolutions down to 2.2 nm have been achieved experimentally. XCT has potential applications in three-dimensional imaging of silicon-based semiconductors, lithography masks, and layered structures like XUV mirrors and solar cells.


2020 ◽  
Vol 640 ◽  
pp. A52
Author(s):  
B. Fuhrmeister ◽  
S. Czesla ◽  
L. Hildebrandt ◽  
E. Nagel ◽  
J. H. M. M. Schmitt ◽  
...  

The He I infrared (IR) triplet at 10 830 Å is known as an activity indicator in solar-type stars and has become a primary diagnostic in exoplanetary transmission spectroscopy. He I IR lines are a tracer of the stellar extreme-ultraviolet irradiation from the transition region and corona. We study the variability of the He I triplet lines in a spectral time series of 319 M dwarf stars that was obtained with the CARMENES high-resolution optical and near-infrared spectrograph at Calar Alto. We detect He I IR line variability in 18% of our sample stars, all of which show Hα in emission. Therefore, we find detectable He I variability in 78% of the sub-sample of stars with Hα emission. Detectable variability is strongly concentrated in the latest spectral sub-types, where the He I lines during quiescence are typically weak. The fraction of stars with detectable He I variation remains lower than 10% for stars earlier than M3.0 V, while it exceeds 30% for the later spectral sub-types. Flares are accompanied by particularly pronounced line variations, including strongly broadened lines with red and blue asymmetries. However, we also find evidence for enhanced He I absorption, which is potentially associated with increased high-energy irradiation levels at flare onset. Generally, He I and Hα line variations tend to be correlated, with Hα being the most sensitive indicator in terms of pseudo-equivalent width variation. This makes the He I triplet a favourable target for planetary transmission spectroscopy.


2018 ◽  
Vol 4 (9) ◽  
pp. eaau3783 ◽  
Author(s):  
Hugo J. B. Marroux ◽  
Ashley P. Fidler ◽  
Daniel M. Neumark ◽  
Stephen R. Leone

Dynamics following excitation with attosecond extreme ultraviolet (XUV) pulses arise from enormous numbers of accessible excited states, complicating the retrieval of state-specific time evolutions. We develop attosecond XUV multidimensional spectroscopy here to separate interfering pathways on a near-infrared (NIR) energy axis, retrieving single state dynamics in argon atoms in a two-dimensional (2D) XUV-NIR spectrum. In this experiment, we measure four-wave mixing signal arising from the interaction of XUV attosecond pulses centered around 15 eV with two few-cycle NIR pulses. The 2D spectrum is created by measuring the emitted XUV signal field spectrum while applying narrowband amplitude and phase modulations to one of the NIR pulses. Application of such a technique to systems of high dimensionality will provide for the observation of state-resolved pure electronic dynamics, in direct analogy to phenomena unraveled by multidimensional spectroscopies at optical frequencies.


2016 ◽  
Vol 94 (2) ◽  
Author(s):  
Wei Cao ◽  
Erika R. Warrick ◽  
Ashley Fidler ◽  
Stephen R. Leone ◽  
Daniel M. Neumark

1986 ◽  
Vol 64 (10) ◽  
pp. 1401-1411
Author(s):  
A. B. Christensen ◽  
R. W. Eastes ◽  
P. D. Feldman ◽  
E. P. Gentieu

Observations of emissions extending from the extreme ultraviolet to the near-infrared region of the spectrum were obtained from a rocket payload flown from Cape Parry, N.W.T., Canada, during the CENTAUR campaign December 7, 1981. The flight, NASA 29.017CE (Terrier-Malemute), was launched near local magnetic noon during an electron-precipitation event in the dayside cleft region. Emission rates versus altitude and zenith angle were obtained for the principal atomic-oxygen emission features OI (989 Å), OI (1304 Å), OI (1356 Å), OI (6300 Å), OI (7774 Å), and OI (8446 Å), as well as HI (1216 Å) and OII (834 Å). Some data were also obtained for the [Formula: see text] (first negative) bands. The results suggest an emission layer peaked in the vicinity of 250 to 300 km. Temporal and spatial fluctuations were most pronounced at apogee and on the downleg portion of the flight. Emissions strongly affected by multiple scattering fluctuated less than optically thin emissions.In this paper, estimates of the input energy flux and characteristic energy are made based on the intensity of the OI (6300 Å) and OI (1356 Å) emissions and the altitude of the emission layer. A value of 0.3 to 0.4 erg/cm2∙s for the energy flux and a characteristic energy of approximately 200 eV are consistent with the observations (1 erg = 0.1 μJ).


2019 ◽  
Vol 151 (11) ◽  
pp. 114305 ◽  
Author(s):  
Ashley P. Fidler ◽  
Hugo J. B. Marroux ◽  
Erika R. Warrick ◽  
Etienne Bloch ◽  
Wei Cao ◽  
...  

2016 ◽  
Vol 18 (21) ◽  
pp. 14644-14653 ◽  
Author(s):  
Adam S. Chatterley ◽  
Florian Lackner ◽  
Daniel M. Neumark ◽  
Stephen R. Leone ◽  
Oliver Gessner

Using femtosecond time-resolved extreme ultraviolet absorption spectroscopy, the dissociation dynamics of the haloalkane 1,2-dibromoethane (DBE) have been explored following strong field ionization by femtosecond near infrared pulses at intensities between 7.5 × 1013 and 2.2 × 1014 W cm−2.


2008 ◽  
Vol 93 (11) ◽  
pp. 111105 ◽  
Author(s):  
Steve Gilbertson ◽  
Hiroki Mashiko ◽  
Chengquan Li ◽  
Eric Moon ◽  
Zenghu Chang

2019 ◽  
Vol 12 (1) ◽  
pp. 225-245 ◽  
Author(s):  
Luke Hanley ◽  
Raveendra Wickramasinghe ◽  
Yeni P. Yung

Lasers with pulse lengths from nanoseconds to femtoseconds and wavelengths from the mid-infrared to extreme ultraviolet (UV) have been used for desorption or ablation in mass spectrometry. Such laser sampling can often benefit from the addition of a second laser for postionization of neutrals. The advantages offered by laser postionization include the ability to forego matrix application, high lateral resolution, decoupling of ionization from desorption, improved analysis of electrically insulating samples, and potential for high sensitivity and depth profiling while minimizing differential detection. A description of postionization by vacuum UV radiation is followed by a consideration of multiphoton, short pulse, and other postionization strategies. The impacts of laser pulse length and wavelength are considered for laser desorption or laser ablation at low pressures. Atomic and molecular analysis via direct laser desorption/ionization using near-infrared ultrashort pulses is described. Finally, the postionization of clusters, the role of gaseous collisions, sampling at ambient pressure, atmospheric pressure photoionization, and the addition of UV postionization to MALDI are considered.


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