# CFEL-UFOX

 2018-05-0210:45 [PUBDB-2018-01885] Journal Article et al Cascaded Interactions Mediated by terahertz radiation Optics express 26(10), 12536 - 12546 (2018) [10.1364/OE.26.012536]   We investigate a regime of parametric amplification in which the pump and signal waves are spectrally separated by only a few hundreds of GHz frequency – therefore resulting in a sub-THz frequency idler wave. Operating in this regime we find an optical parametric amplifier (OPA) behavior which is highly dissimilar to conventional OPAs. [...] OpenAccess: PDF PDF (PDFA); 2018-04-1309:33 [PUBDB-2018-01720] Journal Article et al Velocity-Map Imaging for Emittance Characterization of Multiphoton Electron Emission from a Gold Surface Physical review applied 9(4), 044018 (2018) [10.1103/PhysRevApplied.9.044018]   A velocity-map-imaging spectrometer is demonstrated to characterize the normalized emittance (root-mean-square, rms) of photoemitted electron bunches. Both the two-dimensional spatial distribution and the projected velocity distribution images of photoemitted electrons are recorded by the detection system and analyzed to obtain the normalized emittance (rms). [...] Fulltext: GIF; OpenAccess: PDF PDF (PDFA); 2018-04-0310:25 [PUBDB-2018-01613] Journal Article et al Segmented terahertz electron accelerator and manipulator (STEAM) Nature photonics --, -- (2018) [10.1038/s41566-018-0138-z]   Acceleration and manipulation of electron bunches underlie most electron and X-ray devices used for ultrafast imaging and spectroscopy. New terahertz-driven concepts offer orders-of-magnitude improvements in field strengths, field gradients, laser synchronization and compactness relative to conventional radiofrequency devices, enabling shorter electron bunches and higher resolution with less infrastructure while maintaining high charge capacities (pC), repetition rates (kHz) and stability. [...] Restricted: PDF PDF (PDFA); 2018-03-2913:43 [PUBDB-2018-01602] Journal Article et al 87-W 1018-nm Yb-fiber ultrafast seeding source for cryogenic Yb:YLF amplifier Optics letters 43(8), 1686 - 1689 (2018) [10.1364/OL.43.001686]   We demonstrate a compact and robust Yb-fiber master-oscillator power-amplifier system operating at 1018 nm with 2.5-nm bandwidth and 1-ns stretched pulse duration. It produces 87-W average power and 4.9-μJ pulse energy, constituting a powerful seed source for cryogenically cooled ultrafast Yb: yttrium lithium fluoride (Yb:YLF) amplifiers.. OpenAccess: PDF PDF (PDFA); 2018-03-1514:54 [PUBDB-2018-01486] Journal Article et al Femtosecond 85  μm source based on intrapulse difference-frequency generation of 21  $\mu$m pulses Optics letters 43(6), 1335 - 1338 (2018) [10.1364/OL.43.001335]   We report on a femtosecond ∼8.5 $\mu$m, ∼2  $\mu$J source based on the intrapulse difference-frequency generation (DFG) of 2.1 $\mu$m pulses in an AgGaSe$_2$ (AGSe) crystal. Compared to the conventional ∼ 0.8 or 1 $\mu$m near-infrared (IR) pulses, a ∼ 2  $\mu$m driver for intrapulse DFG can provide more efficient conversion into the wavelengths longer than 5 $\mu$m due to a lower quantum defect and is more suitable for the non-oxide nonlinear crystals that have a relatively low bandgap energy. [...] Published on 2018-02-13. Available in OpenAccess from 2019-02-13.: PDF PDF (PDFA); Restricted: PDF PDF (PDFA); 2018-03-0512:58 [PUBDB-2018-01375] Journal Article et al Near- and Extended-Edge X-Ray-Absorption Fine-Structure Spectroscopy Using Ultrafast Coherent High-Order Harmonic Supercontinua Physical review letters 120(9), 093002 (2018) [10.1103/PhysRevLett.120.093002]   Recent advances in high-order harmonic generation have made it possible to use a tabletop-scale setup to produce spatially and temporally coherent beams of light with bandwidth spanning 12 octaves, from the ultraviolet up to x-ray photon energies >1.6 keV. Here we demonstrate the use of this light for x-ray-absorption spectroscopy at the K- and L-absorption edges of solids at photon energies near 1 keV. [...] OpenAccess: PDF PDF (PDFA); 2018-03-0211:38 [PUBDB-2018-01356] Journal Article et al Pre-chirp managed, core-pumped nonlinear PM fiber amplifier delivering sub-100-fs and high energy (10 nJ) pulses with low noise Optics express 26(5), 6427 - 6438 (2018) [10.1364/OE.26.006427]   We demonstrate a pre-chirp managed amplification (PCMA) system that is based on two stages of core-pumped, polarization maintaining (PM) fiber amplifiers. It produces output pulses with <65 fs duration and >10 nJ pulse energy from single-mode fibers. [...] OpenAccess: PDF PDF (PDFA); 2018-02-2715:48 [PUBDB-2018-01330] Journal Article et al Comparative Spectroscopic Investigation of $\mathrm Tm^{3+}$: Tellurite Glasses for 2-$\mu$m Lasing Applications Applied Sciences 8(3), 333 (2018) [10.3390/app8030333] special issue: "Rare-Earth Doping for Optical Applications"   We performed a comparative spectroscopic analysis on three novel $\mathrm Tm^{3+}$:tellurite-based glasses with the following compositions $\mathrm {Tm^{3+}Tm_2O_3:TeO_2-ZnO}$ (TeZnTm), $\mathrm{Tm_2O_3:TeO_2-Nb_2O_5 (TeNbTm)}$, and $\mathrm{Tm^{3+}:TeO_2-K_2O-Nb_2O_5}$ (TeNbKTm), primarily for 2-m laser applications. Tellurite glasses were prepared at different doping concentrations in order to investigate the effect of $\mathrm{Tm^{3+}}$ ion concentration as well as host composition on the stimulated emission cross sections and the luminescence quantum efficiencies [...] OpenAccess: Comparative - PDF PDF (PDFA); applsci-08-00333 - PDF PDF (PDFA); 2018-02-0615:20 [PUBDB-2018-01078] Conference Presentation (Invited) et al Frequency-shifted sources for Terahertz-driven linear electron acceleration SPIE Photonics West 2018, San Francisco, CASan Francisco, CA, USA, 27 Jan 2018 - 1 Feb 2018   The generation of THz-frequency radiation via nonlinear parametric frequency down-conversion has long been driven by the spectroscopy and imaging communities. As a result, little efforts have been undertaken toward the generation of high energy THz-frequency pulses. [...] OpenAccess: PDF PDF (PDFA); 2018-02-0514:49 [PUBDB-2018-01055] Dissertation / PhD Thesis Ippen, E. P. High field terathertz radiation : Conduits to synchronized hyper spectral systems , 267 pp. (2018) = Dissertation, Massachusetts Institute of Technology, 2018 Laser technology has seen significant development since its inception in 1960. After the first experiments of nonlinear phenomena in optics, the development of the mode-locked laser has led to rapid proliferation of the study of nonlinear frequency conversion techniques-enabling the conversion of light from the infra-red, all the way to the soft X-Ray region. [...]