All-optical spatio-temporal control of electron emission from SiO2 nanospheres with femtosecond two-color laser fields

Field localization by nanostructures illuminated with laser pulses of well-defined waveform enables spatio-temporal tailoring of the near-fields for sub-cycle control of electron dynamics at the nanoscale. Here, we apply intense linearly-polarized two-color laser pulses for all-optical control of the highest energy electron emission from SiO2 nanoparticles. For the size regime where light propagation effects become important, we demonstrate the possibility to control the preferential emission angle of a considerable fraction of the fastest electrons by varying the relative phase of the two-color field. Trajectory based semi-classical simulations show that for the investigated nanoparticle size range the directional steering can be attributed to the two-color effect on the electron trajectories, while the accompanied modification of the spatial distribution of the ionization rate on the nanoparticle surface has only a minor effect. © 2019 The Author(s). Published by IOP Publishing Ltd on behalf of the Institute of Physics and Deutsche Physikalische Gesellschaf

Few-cycle laser driven reaction nanoscopy on aerosolized silica nanoparticles

Nanoparticles offer unique properties as photocatalysts with large surface areas. Under irradiation with light, the associated near-fields can induce, enhance, and control molecular adsorbate reactions on the nanoscale. So far, however, there is no simple method available to spatially resolve the near-field induced reaction yield on the surface of nanoparticles. Here we close this gap by introducing reaction nanoscopy based on three-dimensional momentum-resolved photoionization. The technique is demonstrated for the spatially selective proton generation in few-cycle laser-induced dissociative ionization of ethanol and water on SiO2 nanoparticles, resolving a pronounced variation across the particle surface. The results are modeled and reproduced qualitatively by electrostatic and quasi-classical mean-field Mie Monte-Carlo ((MC)-C-3) calculations. Reaction nanoscopy is suited for a wide range of isolated nanosystems and can provide spatially resolved ultrafast reaction dynamics on nanoparticles, clusters, and droplets

Few-cycle laser driven reaction nanoscopy on aerosolized silica nanoparticles

Nanoparticles offer unique properties as photocatalysts with large surface areas. Under irradiation with light, the associated near-fields can induce, enhance, and control molecular adsorbate reactions on the nanoscale. So far, however, there is no simple method available to spatially resolve the near-field induced reaction yield on the surface of nanoparticles. Here we close this gap by introducing reaction nanoscopy based on three-dimensional momentum-resolved photoionization. The technique is demonstrated for the spatially selective proton generation in few-cycle laser-induced dissociative ionization of ethanol and water on SiO2 nanoparticles, resolving a pronounced variation across the particle surface. The results are modeled and reproduced qualitatively by electrostatic and quasi-classical mean-field Mie Monte-Carlo (M3C) calculations. Reaction nanoscopy is suited for a wide range of isolated nanosystems and can provide spatially resolved ultrafast reaction dynamics on nanoparticles, clusters, and droplets

All-optical spatio-temporal control of electron emission from SiO2 nanospheres with femtosecond two-color laser fields

Field localization by nanostructures illuminated with laser pulses of well-defined waveform enables spatio-temporal tailoring of the near-fields for sub-cycle control of electron dynamics at the nanoscale. Here, we apply intense linearly-polarized two-color laser pulses for all-optical control of the highest energy electron emission from SiO2 nanoparticles. For the size regime where light propagation effects become important, we demonstrate the possibility to control the preferential emission angle of a considerable fraction of the fastest electrons by varying the relative phase of the two-color field. Trajectory based semi-classical simulations show that for the investigated nanoparticle size range the directional steering can be attributed to the two-color effect on the electron trajectories, while the accompanied modification of the spatial distribution of the ionization rate on the nanoparticle surface has only a minor effect.11Ysciescopu

Synthese von polymeren kolloidalen Kristallen auf Basis von Acrylnitril und deren thermische Behandlung zu porösen Kohlenstoffen

Ziel der vorliegenden Arbeit war die Synthese von porösen Kohlenstoffmaterialien aus polyacrylnitrilbasierten Kern-Schale-Partikeln. Poröse Kohlenstoffmaterialien stellen einen wichtigen Baustein für die Forschung in der Batterie- und Superkondensatortechnik sowie in der Katalyse dar. Die Kern-Schale-Partikel können über die starved-feed Emulsionspolymerisation mit gezielt einstellbarer Größe und definierbarem Verhältnis zwischen Kern und Schale synthetisiert werden. Dadurch wird eine vorab definierbare Porengröße für das finale Kohlenstoffmaterial ermöglicht. Während der folgenden thermischen Prozesse wird das polymere Kernmaterial zersetzt und es kann eine poröse Kohlenstoffstruktur erhalten werden. Ausgehend von den Partikeln wurden zwei Wege zur Herstellung von geordneten porösen Kohlenstoffen verfolgt. Zum einen wurden kolloidal kristalline Filme mittels des Schmelze-Scher-Verfahrens hergestellt. Die so erhaltenen Opalfilme wurden zunächst unter oxidativer Atmosphäre stabilisiert und anschließend unter Inertgas verkohlt. Die Stabilisierung wirkt sich dabei stark auf die Optik der Opalfilme aus, was sie auch für optische und sensorische Anwendungen interessant macht. Zum anderen wurden die reinen getrockneten Partikel, die durch den Trocknungsprozess eine hoch geordnete Struktur ausbilden, ebenfalls unter oxidativer Atmosphäre stabilisiert. Anschließend wurde eine Verkohlung entweder unter inerter oder in aktivierender ammoniakalischer Atmosphäre durchgeführt. Durch letztere solle eine Verbesserung der inneren Oberfläche, sowie der Erhalt des Stickstoffs im finalen Kohlenstoffgerüst gewährleistet werden

Health and life insurance-related problems in very long-term cancer survivors in Germany: a population-based study

PURPOSE: Limited research suggests that cancer survivors have problems with insurance. Our study aimed to gain insight into the proportion of very long-term (14–24 years post-diagnosis) survivors of breast, colorectal, and prostate cancers who had problems with health (HI) and life (LI) insurance. METHODS: We used data from CAESAR (CAncEr Survivorship—A multi-Regional population-based study). Participants completed questions on change in insurance providers since cancer diagnosis, problems with requesting (additional) HI or LI, and how potential problems were resolved. We conducted logistic regression to determine factors associated with change in statutory HI. RESULTS: Of the 2714 respondents, 174 (6%) reported having changed HI providers. Most switched between different statutory HI providers (86%), 9% from statutory to private, and 5% from private to statutory. Respondents who changed statutory HI providers were more likely to be prostate cancer survivors (OR 2.79, 95% CI 1.01–7.68) while being ≥ 65 years at time of diagnosis (OR 0.58, 95% CI 0.35–0.96) and having ≥ 2 comorbid conditions (OR 0.61, 95% CI 0.40–0.92) were associated with reduced odds for change. Problems in changing HI were minimal and were resolved with additional contribution. Of the 310 respondents who tried to get LI, 25 respondents reported having difficulties, of whom the majority had their request rejected. CONCLUSION: Most cancer survivors did not change their HI nor tried to buy LI after cancer diagnosis. Problems with changing statutory HI were generally resolved with additional contribution while the main problem encountered when buying LI was rejection of request

All-optical spatio-temporal control of electron emission from SiO₂ nanospheres with femtosecond two-color laser fields

Field localization by nanostructures illuminated with laser pulses of well-defined waveform enables spatio-temporal tailoring of the near-fields for sub-cycle control of electron dynamics at the nanoscale. Here, we apply intense linearly-polarized two-color laser pulses for all-optical control of the highest energy electron emission from SiO₂ nanoparticles. For the size regime where light propagation effects become important, we demonstrate the possibility to control the preferential emission angle of a considerable fraction of the fastest electrons by varying the relative phase of the two-color field. Trajectory based semi-classical simulations show that for the investigated nanoparticle size range the directional steering can be attributed to the two-color effect on the electron trajectories, while the accompanied modification of the spatial distribution of the ionization rate on the nanoparticle surface has only a minor effect