Control over Extreme-Ultraviolet High-Harmonic Generation from Gases and Solids

The light source that has revolutionized attosecond science over the last decades is based on the process of high-harmonic generation (HHG), which is a unique method to generate a broadband coherent spectrum extending into the extreme-ultraviolet (XUV) range. The temporal and spatial resolution of HHG enables investigation of strong-field light-matter interaction in the ultrafast and ultrasmall dimensions, and finds applications in attosecond science, lensless imaging, and industrial metrology. Unfortunately, the intrinsic low conversion efficiency of HHG and the limited methods to control the generated XUV wavefront, slow down present research and future development of applications that are based on HHG. Control over the HHG process is essential to improve the conversion efficiency and XUV wavefront characteristics, in order to facilitate next-generation attosecond science and metrology. This thesis presents experimental techniques and results that demonstrate control over both gas-based and solid-based HHG in the extreme-ultraviolet regime. Additionally, the underlying mechanism and working principles are explained through theoretical models and simulations. In Chapter 4, we demonstrate divergence and yield optimization in polarization controlled two-color gas-based HHG. Imaging, spectroscopy, and metrology applications using HHG sources require high XUV brightness, related to the conversion efficiency and the focusability of the generated XUV pulses. We systematically investigate, both experimentally and theoretically, the effect of the relative polarization between the fundamental and its second harmonic in two-color HHG, and compare the results to a one-color configuration. In a perpendicular two-color field, the relative phase between the two colors can be used to manipulate the long or the short trajectories, allowing control over the divergence of the harmonics. In a parallel two-color field, the relative phase can be used to modify the ionization rate to select trajectories and additionally allows to enhance the total yield. Next, we describe extreme-ultraviolet shaping and imaging by HHG from nanostructured silica in Chapter 5. Tailoring of any XUV wavefront after generation is challenged by the lack of efficient optical elements and limits HHG applications. We demonstrate how HHG from a structured generation medium enables control over the phase, amplitude, and polarization properties of extreme-ultraviolet pulses. Moreover, we use the emitted patterns to reconstruct height profiles, probe the near-field confinement in nanostructures below the diffraction limit of the fundamental, and image complex structures using the coherent diffractive emission from the structures. In another experiment, we establish efficient extreme-ultraviolet high-order wavemixing from laser-dressed silica, described in Chapter 6. Solid-based HHG allows to produce a coherent, broadband, extreme-ultraviolet light source with tailored emission profiles, but is put at disadvantage due to the low conversion efficiency from infrared to XUV photons. Here, we overcome the low conversion efficiency by driving the HHG simultaneously with the fundamental and its second harmonic, in a non-collinear geometry. The observed high-order wave mixing emission follows perturbative intensity scalings and enhances the XUV efficiency by at least one order of magnitude. The underlying generation mechanism is described by a quantum theory, that reveals that solid HHG is boosted through laser-dressed states. Finally, we demonstrate transient grating high-harmonic spectroscopy in MgO in Chapter 7, and investigate how an excited carrier population influences solid-state HHG. Two crossed 266-nm pulses induce a transient grating of excited carrier population due to two-photon absorption in the MgO. The modification of the relative amplitude and phase of the harmonics at the generation plane results in diffraction in the far field. Preliminary analysis demonstrates that both the macroscopic propagation effects onto the fundamental and the microscopic generation mechanism of the HHG process contribute to the amplitude and phase modulation

Efficient extreme-ultraviolet high-order wave mixing from laser-dressed silica

The emission of high-order harmonics from solids \cite{ghimire11a,schubert14a,luu15a,golde08a} under intense laser-pulse irradiation is revolutionizing our understanding of strong-field solid-light interactions \cite{ghimire11a,schubert14a,luu15a,vampa15b,yoshikawa17a,hafez18a,jurgens20a}, while simultaneously opening avenues towards novel, all-solid, coherent, short-wavelength table-top sources with tailored emission profiles and nanoscale light-field control\cite{franz19a,roscamCLEO21}. To date, broadband spectra have been generated well into the extreme-ultraviolet (XUV) \cite{luu15a,luu18b,han19a,uzan20a}, but the comparatively low conversion efficiency still lags behind gas-based high-harmonic generation (HHG) sources \cite{luu15a,luu18b}, and have hindered wider-spread applications. Here, we overcome the low conversion efficiency by two-color wave mixing. A quantum theory reveals that our experiments follow a novel generation mechanism where the conventional interband and intraband nonlinear dynamics are boosted by Floquet-Bloch dressed states, that make solid HHG in the XUV more efficient by at least one order of magnitude. Emission intensity scalings that follow perturbative optical wave mixing, combined with the angular separation of the emitted frequencies, make our approach a decisive step for all-solid coherent XUV sources and for studying light-engineered materials

Reply to Letter to the Editor HEP-20-0593

We sincerely thank Dr. Javitt for his interest in and perspective on our paper (1). He indicates that aspecific effects of Myrcludex B should be considered an explanation for increased biliary cholesterol and phospholipid secretion after Myrcludex B treatment as partial hepatectomy (PH) also leads to an increased contribution of pericentral hepatocytes to bile salt uptake and secretion but biliary cholesterol and phospholipid secretion are not affected. In our opinion, non-specific Myrcludex B-induced activation of canalicular or sinusoidal transporters seems unlikely given the absence of NTCP homology with these transporters and our data from experiments with SR-B1 or ABCG8 null mice. Myrcludex B is an NTCP-specific peptide showing minimal uptake by hepatocytes

Blocking Sodium-Taurocholate Cotransporting Polypeptide Stimulates Biliary Cholesterol and Phospholipid Secretion in Mice

Active secretion of bile salts into the canalicular lumen drives bile formation and promotes biliary cholesterol and phospholipid output. Disrupting hepatic bile salt uptake, by inhibition of sodium-taurocholate cotransporting polypetide (NTCP; Slc10a1) with Myrcludex B, is expected to limit bile salt flux through the liver and thereby to decrease biliary lipid excretion. Here, we show that Myrcludex B–mediated NTCP inhibition actually causes an increase in biliary cholesterol and phospholipid excretion whereas biliary bile salt output and bile salt composition remains unchanged. Increased lysosomal discharge into bile was excluded as a potential contributor to increased biliary lipid secretion. Induction of cholesterol secretion was not a consequence of increased ATP-binding cassette subfamily G member 5/8 activity given that NTCP inhibition still promoted cholesterol excretion in Abcg8−/− mice. Stimulatory effects of NTCP inhibition were maintained in Sr-b1−/− mice, eliminating the possibility that the increase in biliary lipids was derived from enhanced uptake of high-density lipoprotein–derived lipids. NTCP inhibition shifts bile salt uptake, which is generally more periportally restricted, toward pericentral hepatocytes, as was visualized using a fluorescently labeled conjugated bile salt. As a consequence, exposure of the canalicular membrane to bile salts was increased, allowing for more cholesterol and phospholipid molecules to be excreted per bile salt. Conclusion: NTCP inhibition increases biliary lipid secretion, which is independent of alterations in bile salt output, biliary bile salt hydrophobicity, or increased activity of dedicated cholesterol and phospholipid transporters. Instead, NTCP inhibition shifts hepatic bile salt uptake from mainly periportal hepatocytes toward pericentral hepatocytes, thereby increasing exposure of the canalicular membrane to bile salts linking to increased biliary cholesterol secretion. This process provides an additional level of control to biliary cholesterol and phospholipid secretion

Blocking Sodium-Taurocholate Cotransporting Polypeptide Stimulates Biliary Cholesterol and Phospholipid Secretion in Mice

Active secretion of bile salts into the canalicular lumen drives bile formation and promotes biliary cholesterol and phospholipid output. Disrupting hepatic bile salt uptake, by inhibition of sodium‐taurocholate cotransporting polypetide (NTCP; Slc10a1) with Myrcludex B, is expected to limit bile salt flux through the liver and thereby to decrease biliary lipid excretion. Here, we show that Myrcludex B–mediated NTCP inhibition actually causes an increase in biliary cholesterol and phospholipid excretion whereas biliary bile salt output and bile salt composition remains unchanged. Increased lysosomal discharge into bile was excluded as a potential contributor to increased biliary lipid secretion. Induction of cholesterol secretion was not a consequence of increased ATP‐binding cassette subfamily G member 5/8 activity given that NTCP inhibition still promoted cholesterol excretion in Abcg8−/− mice. Stimulatory effects of NTCP inhibition were maintained in Sr‐b1−/− mice, eliminating the possibility that the increase in biliary lipids was derived from enhanced uptake of high‐density lipoprotein–derived lipids. NTCP inhibition shifts bile salt uptake, which is generally more periportally restricted, toward pericentral hepatocytes, as was visualized using a fluorescently labeled conjugated bile salt. As a consequence, exposure of the canalicular membrane to bile salts was increased, allowing for more cholesterol and phospholipid molecules to be excreted per bile salt. Conclusion: NTCP inhibition increases biliary lipid secretion, which is independent of alterations in bile salt output, biliary bile salt hydrophobicity, or increased activity of dedicated cholesterol and phospholipid transporters. Instead, NTCP inhibition shifts hepatic bile salt uptake from mainly periportal hepatocytes toward pericentral hepatocytes, thereby increasing exposure of the canalicular membrane to bile salts linking to increased biliary cholesterol secretion. This process provides an additional level of control to biliary cholesterol and phospholipid secretion.Biopharmaceutic

Children and Their Parents: A Comparative Study of the Legal Position of Children with Regard to Their Intentional and Biological Parents in English and Dutch Law

This is a book about children and their parents. There are many different kinds of children and at least about as many different kinds of parents. In addition to the many different disciplines that study children and their parents, such as sociology, psychology, child studies and gender studies, to name but a few, this study concerns a legal question with regard to the parent-child relationship, namely how the law assigns parents to children. This subject is approached in a comparative legal perspective and covers England and The Netherlands. The book contains a detailed comparison and analysis of the manner in which the law in the two jurisdictions assigns the status of legal parent and/or attributes parental responsibility to the child’s biological and intentional parents. The concept ‘procreational responsibility’, which is introduced in the concluding chapter of the book, may be used as a tool to assess and reform existing regulations on legal parent-child relationships. The structure of the book, which is based on a categorisation of different family types in a ‘family tree’, enables the reader to have easy access to family-specific information.FdR – Publicaties zonder aanstelling Universiteit Leide