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The realization of a table-top tunable deep-ultraviolet (UV) laser source with excellent noise properties would significantly benefit the scientific community, particularly within imaging and spectroscopic applications, where source noise has a crucial role. Here we provide a thorough characterization of the pulse-to-pulse relative intensity noise (RIN) of such a deep-UV source based on an argon (Ar)-filled anti-resonant hollow-core (AR HC) fiber. Suitable pump pulses are produced using a compact commercially available laser centered at 1030 nm with a pulse duration of 400 fs, followed by a nonlinear compression stage that generates pulses with 30 fs duration, 24.2 μJ energy at 100 kHz repetition rate and a RIN of

Deep-UV radiation is achieved through dispersive wave generation in an argon-filled anti-resonant fiber utilizing a nonlinearly compressed 1030nm pump. Relative intensity noise is characterized at 280nm, with 1.6% achieved for optimal argon-pressure and pump parameters.

Ultrafast, light-induced dynamics in copper-zinc-tin-sulfide (CZTS) photovoltaic nanoparticles are investigated through a combination of optical and x-ray transient absorption spectroscopy. Laser-pump, x-ray-probe spectroscopy on a colloidal CZTS nanoparticle ink yields element-specificity, which reveals a rapid photo-induced shift of electron density away from Cu-sites, affecting the molecular orbital occupation and structure of CZTS. We observe the formation of a stable charge-separated and thermally excited structure, which persists for nanoseconds and involves an increased charge density at the Zn sites. Combined with density functional theory calculations, the results provide new insight into the structural and electronic dynamics of CZTS absorbers for solar cells.

Time-resolved X-ray scattering patterns from photoexcited molecules in solution are in many cases anisotropic at the ultrafast time scales accessible at X-ray Free Electron Lasers (XFELs). This anisotropy arises from the interaction of a linearly polarized UV-vis pump laser pulse with the sample, which induces anisotropic structural changes that can be captured by femtosecond X-ray pulses. In this work we describe a method for quantitative analysis of the anisotropic scattering signal arising from an ensemble of molecules and we demonstrate how its use can enhance the structural sensitivity of the time-resolved X-ray scattering experiment. We apply this method on time-resolved X-ray scattering patterns measured upon photoexcitation of a solvated di-platinum complex at an XFEL and explore the key parameters involved. We show that a combined analysis of the anisotropic and isotropic difference scattering signals in this experiment allows a more precise determination of the main photoinduced structural change in the solute, i.e. the change in Pt-Pt bond length, and yields more information on the excitation channels than the analysis of the isotropic scattering only. Finally, we discuss how the anisotropic transient response of the solvent can enable the determination of key experimental parameters such as the Instrument Response Function., Accepted for publication in Journal of Synchrotron Radiation

Photovoltaic processesof the earth abundant and non-toxic Cu2ZnSnS4 (CZTS) absorbermaterial in 3. generation solar cells can be investigated by time resolved X-ray absorptionspectroscopy (TR-XAS) using a synchrotron-based X-ray source and synchronizedlaser excitation (pump-probe method). Such experiments require high qualityCZTS [1] stabilized as a nanoparticle (NP) ink as a model system, which is alsoapplicable for low-cost up-scalable roll-to-roll (R2R) printing.