Microwavephysics and Atmospheric Physics
Biomedizinische Photonik
Ultrafast Science and Technology
HS 2017  ·  FS 2017
HS 2016  ·  FS 2016
HS 2015  ·  FS 2015
HS 2014  ·  FS 2014
HS 2013  ·  FS 2013
HS 2012  ·  FS 2012
HS 2011  ·  FS 2011
Last update: 18.10.2017
FS 2016: Seminare über Ultrafast Science and Technology
Thursday 11:15am
Vorträge, die innerhalb der nächsten Tage stattfinden, sind speziell markiert.
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Donnerstag, 10.03.2016

Internal seminar

Zeit: 11:15 Uhr
Hörsaal: B116
 
Prof. Thomas Feurer
Institute of Applied Physics
University of Bern

 
Donnerstag, 17.03.2016

Joint seminar Department of Chemistry and Biochemistry / Institute of Applied Physics

Photosynthetic Light Harvesting: An Overview

Zeit: 11:15 Uhr
Hörsaal: DCB/S481
 
Prof. Gregory Scholes
Princeton University

 
Donnerstag, 24.03.2016

Gas discharges in hollow core fibers and applications

Zeit: 11:15 Uhr
Hörsaal: B116
 
Christa Biberstein
Institute of Applied Physics
University of Bern

Using external micro-electrodes and high voltage at kHz frequencies we generate a gas discharge in hollow core fibres. We present first successful experiments in capillaries, and discuss further steps to extend this principle in order to create a HeNe laser in a fibre.

 
Donnerstag, 31.03.2016

no seminar (Easter holiday)

Zeit: 00:00 Uhr
Hörsaal:
 

 
Donnerstag, 07.04.2016

Detection of Gravitational Waves: The GW150914 Event

Zeit: 11:15 Uhr
Hörsaal: B116
 
Dr. Andrew Lundgren
Max Planck Institute for Gravitational Physics
Albert Einstein Institute
Hannover, Germany

The first observation of gravitational waves from the merger of two black holes has recently been announced. I'll talk about how the detection was made, how we confirmed its astrophysical origin, and how we measured its properties. I'll also give a personal account of the first few hours and talk about prospects for the future.

 
Donnerstag, 14.04.2016

Single Shot detection for UV-Spectroscopy

Zeit: 11:15 Uhr
Hörsaal: B116
 
Dr. Georg Achazi
Institute of Applied Physics
University of Bern

I present new concepts for using single shot detection to characterize UV pulses I spectroscopy. By exploiting the benefits of this technique we constructed a SD-Frog for the characterisation of 1 µJ UV-pulses and developed a new concept for single shot Fouriertransform Spectral Interferometry that allows heterodyne detection without phase stabilisation. Both methods are a huge step towards the goal of our group to extend the 2D-photon-echo-spectroscopy into the deep-UV.

 
Donnerstag, 21.04.2016

Joint seminar Department of Chemistry and Biochemistry / Institute of Applied Physics

Addressing basic questions on photoinduced electron transfer processes using ultrafast spectroscopy

Zeit: 11:15 Uhr
Hörsaal: DCB/S481
 
Prof. Eric Vauthey
Département de Chimie Physique
Université de Genève

 
Donnerstag, 28.04.2016

University of Geneva Applied Physics

Quantum Nonlinear Optics (extraordinary colloquium)

Nonlinear Optics Meets the Quantum World

Zeit: 11:00 Uhr
Hörsaal: UniGE/Auditoire
 
Prof. Robert W. Boyd
The Institute of Optics
University of Rochester

 
Donnerstag, 05.05.2016

no seminar (Ascension Day)

Zeit: 00:00 Uhr
Hörsaal:
 

 
Donnerstag, 12.05.2016

Optimal measurements for non-local correlations with energy-time entangled photons

Zeit: 11:15 Uhr
Hörsaal: B116
 
Sacha Schwarz
Institute of Applied Physics
University of Bern

A practical problem in quantum information-processing applications is to find the experimental setup that maximizes the nonlocality of correlations with respect to some suitable measure such as the violation of Bell inequalities. Employing this strength of violation as a measure has however some drawbacks, especially in the consideration of more complex Bell scenarios. Therefore an alternative measure of nonlocality may be used like the minimal amount of classical communication required for simulating nonlocal correlations; we call the corresponding quantity ’nonlocal capacity’.

In my talk, I will first focus on the basic concepts behind Bell experiments. In a second step, I introduce the nonlocal capacity as measure of nonlocality and compare this quantity with the strength of Bell inequality violations. In the third part I show the link to our experiments and give a short overview of ongoing improvements on the manipulation and detection part of our setup.

 
Donnerstag, 19.05.2016

Ultrafast energy transfer dynamics in DNA-hosted multichromophoric systems investigated by DUV-to-Vis femtosecond pump-probe spectroscopy

Zeit: 11:15 Uhr
Hörsaal: B116
 
Maryam Nazari Haghighi Pashaki
Institute of Applied Physics
University of Bern

We recently investigated photophysics of a family of DNA-hosted multichromophoric arrays, which shows a very efficient energy transfer (EnT) over nanometers with unitary quantum yield and a very high absorption cross-section. These two features make them promising systems as light-harvesting antennas for supramolecular devices. However, the mechanism responsible for such an efficient EnT is still elusive. To clarify it, I have been studying excited-state dynamics of these systems by DUV-to-Vis femtosecond transient absorption spectroscopy. In this seminar I will show the recent improvements of set-up and the outcome of our investigation.

 
Donnerstag, 26.05.2016

Ceramics and Nanocomposite Research at Empa’s Laboratory for High Performance Ceramics

Zeit: 11:15 Uhr
Hörsaal: B116
 
Prof. Thomas Graule
EMPA
Dübendorf

High Performance Ceramic Materials and Nanocomposite Materials offer great perspectives in different fields, like in energy technology, clean technologies and in machine and computer industry. The application of nanopowders opens herewith the opportunity to develop nanocomposites with improved performance, e.g. relevant in fuel cell research or in advanced coating technologies. Some recent projects and activities covering these topics are presented in the first part of the lecture. The efficient stabilisation of ceramic based nano powders is a prerequisite for the achievement of these highly reliable ceramic nanomaterials. Agglomeration as a main origin of flaws can be avoided using different concepts to increase the separation barrier by electrostatic or steric means. Recently we performed detailed studies applying anion and cation type copolymers for the surface modification and stabilisation of alumina and zirconia submicron and nanoparticles. The studies were performed in order to develop a basic understanding of the mechanism of steric stabilisation in aqueous media [1-4]. We present here additionally new concepts to apply cationic comb copolymers as a promising alternative in case of the stabilisation of titania and silica. The effectiveness of the anionic and cationic dispersants is evaluated on the basis of adsorption, zeta potential measurements, rheology and particle size measurements [5-6].

References 1. Y. De Hazan, J. Heinecke, A. Weber, T. Graule, High Solids Loading Ceramic colloidal Dispersions in UV Curable Media via Comb polyelectrolyte Surfactants, J. Colloid Interf. Sci. 337 (2009) 66–74. 2. M. Wozniak, Y. de Hazan, T. Graule, D. Kata, Rheology of UV curable colloidal silica dispersions for rapid prototyping applications, J. Eur. Cer. Soc. 2011, 31, 2221-2229. 3. Y. de Hazan, V. Märkl, J. Heinecke, C. Aneziris, T. Graule, Functional ceramic and nanocomposite fibers, cellular articles and microspheres via radiation curable colloidal dispersions, J. Eur. Cer. Soc. 2011, 31, 2601-2600. 4. V. Klimkevicius, T. Graule, R. Makuska, Effect of structure of cationic comb copolymers on their adsorption and stabilization of titania nanoparticles, Langmuir 2015, 31, 2074-2083. 5. Y. de Hazan, Wilkens-Heinecke J.; Graule T., Modeling the effect of molecular architecture of comb polymers on the behavior of Al2O3 dispersions using charge/composition factors (CCF), Colloid Polymer. Sci. 2014, 292, 7, 1701-1710. 6. Klimkevicius V., Makuska R., Graule T., Rheology of titania based ceramic nanodispersions stabilized by cationic comb copolymers, Applied Rheology, accepted February 2016

 
Donnerstag, 02.06.2016

High field terahertz spectroscopy on gated single layer graphene

Zeit: 11:15 Uhr
Hörsaal: B116
 
Gregory Gäumann
Institute of Applied Physics
University of Bern

We studied the non-linear optical properties of single layer graphene in the THz region at temperatures between 20 K and 300 K. With the use of a gate the carrier concentration was tuned from the Dirac point to high concentrations. Time-domain spectra are analyzed to study saturable absorption and high order harmonic generation.

 
Montag, 27.06.2016

PhD Defense: Energy-Time Entangled Two-Photon States for Quantum Information and Nonlinear Spectroscopy

Zeit: 10:15 Uhr
Hörsaal: B5
 
Stefan Lerch
Institute of Applied Physics
University of Bern