past events

Thursday 30. June 2016

IMPRS monthly meeting

 

Organisation: Luo Qi (MPL/ Chekhova Research Group)

Talk: Efficient coupling of light and a single two level atom in free space

Speaker: Dr. Bharath Srivathsan (MPL / Leuchs Division)

Place: MPL / Large seminar room (*429/435)

Abstract:

The interaction of light with a single atom is among one of the most fundamental problems in quantum optics. A great number of effects has been studied and many applications utilizing the interaction of a light field with single atoms have been successfully demonstrated. Nevertheless the efficiency of such an interaction in free space has been quite small in general. In this talk I will present a way to achieve a near perfect coupling in free space using a parabolic mirror with a two level atom at its focus. I will further discuss some of our recent results on characterizing the coupling efficiency of light to a single trapped 174Yb+ ion.

Thursday 16. June 2016

IMPRS monthly meeting

 

Organisation: Roland Lauter (FAU/ Institute for Theoretical Physics II)

Talk: Phase Transitions and Spontaneous Symmetry Breaking in Open Quantum Systems

Speaker: Dr Carlos Navarrete-Benlloch (Institute for Theoretical Physics II, FAU)

Place: MPL / Large seminar room (*429/435)

Abstract:

Closed systems, fully described by a Hamiltonian, undergo a phase transition when the ground-state expectation value of some observable shows a sudden change of behaviour as a system parameter is varied. For systems with some intrinsic symmetry, such a “critical point” usually separates two very distinct phases: one with a unique ground state that preserves the symmetry, and another where the system presents several degenerate ground states which are connected by the symmetry transformation. In the second phase, the process by which the system chooses one of the ground states is consequently known as “spontaneous symmetry breaking”, and many interesting physical phenomena are derived from it (most prominently the Higgs mechanism of the Standard Model of particle physics).

While phase transitions are well understood in closed systems, the situation is rather different in open systems, that is, systems in contact with an environment to which they loose energy and information. For any value of its parameters, dissipation usually drives the system into a unique equilibrium state, and hence, one may think that phase transitions and, especially, spontaneous symmetry breaking play little role on such scenario, if any. Through the simple (but significant) example of degenerate parametric oscillation, a paradigmatic quantum-optical dissipative model containing a discrete symmetry, in this talk I will try to convince you that the situation is much more subtle than it looks, and indeed phase transitions and spontaneous symmetry breaking provide valuable and deep insight into the physics of open quantum systems.

Apart from introducing the topic from a general point of view, I will briefly discuss different modern quantum-optical technologies where the physics of dissipative phase transitions and spontaneous symmetry breaking play a major role. Most of my current work is focused on such technologies which include, e.g., nonlinear optics, opto- and electro-mechanical devices, cold atoms, and superconducting circuits.

Thursday 19. May 2016

IMPRS monthly meeting

 

Organisation: Pooria Hosseini (MPL/ Russell Division)

Talk: Attractive natures in a set of a highly-discrete coherent spectrum and its application to an extreme laser technology

Speaker: Dr Masayuki Katsuragawa (University of Electro-communications, Tokyo, Japan)

Place: MPL / Large seminar room (*429/435)

Abstract:

We discuss attractive natures in linear and nonlinear optical processes composed of a highly-discrete coherent spectrum which can be generated by adiabatically driving a Raman coherence. In the linear optical process, a train of transform-limited 1.8 fs pulses is generated by simply inserting transparent dispersive plates [1, 2]. On the other hand, in the nonlinear optical processes, various artificial manipulations of optical frequency conversion processes are shown, where a single-frequency tunable laser which can cover the whole spectral region of 100 nm to 30 µm is typically demonstrated [3].

Reference

[1] K. Yoshii, J. K. Anthony, and M. Katsuragawa, The simplest rout to generating a train of attosecond pulses, Light: Science & Applications, (2013) 2, e58.; arXiv:1207.6780 (2012).

[2] K. Yoshii, Y. Nakamura, K. Hagihara, and M. Katsuragawa: Generation of a Train of Ultrashort Pulses by Simply Inserting Transparent Plates on the Optical Path, CLEO/QELS 2014, FThD1.5.

[3] Jian Zheng and Masayuki Katsuragawa, "Freely designable optical frequency conversion in Raman-resonant four-wave-mixing process," Scientific Reports 5, 8874 (2015).; arXiv: 1406.3921 (2014).

Monday 25. April 2016

IMPRS symposium for the Science of Light

 

The International Max Planck Research School (IMPRS) symposium for the Science of Light is a joint initiative between the graduate schools (IMPRS-PL and IMPRS-APS) of the Max Planck Institute for the Science of Light (MPL) and the Max Planck Institute for Quantum Optics (MPQ).

With this symposium, we plan to bring 100 students together with leading scientists from diverse physics communities, covering the topical range from technical and classical optics, imaging technologies, optical manipulation, nano photonics, non-linear optics, quantum communication, ultrashort pulses generation and more.

The seminar will provide excellent opportunities for young researchers to get introduced to the current leading research in the above-mentioned areas. In addition, it will foster the discussion between guest speakers and attendees by providing joint social events each evening.

Please find more details on the event's website.

Thursday 31. March 2016

IMPRS monthly meeting

 

Organisation: Hsuan-Wei Liu (MPL/ Sandoghdar Division)

Talk: Spontaneous emission control in hybrid photonics systems

Speaker: Dr. Martin Frimmer (Photonics laboratory, Dept. of Information Technology and Electrical Engineering, ETH Zürich)

Place: MPL / Large seminar room (*429/435)

Abstract:

Nanophotonics is the science of controlling all aspects of light generation, propagation, and absorption on length scales smaller than the wavelength. This talk focuses on controlling the spontaneous emission of photons. The quantity of paramount importance in the context of spontaneous emission control is the local density of optical states which can be engineered by designing the electromagnetic environment of the source. After reviewing the established nanophotonic tools for spontaneous emission control, we turn to hybrid photonic systems harnessing the sometimes counter-intuitive electromagnetic interplay between several building blocks.

Thursday 25. February 2016

IMPRS monthly meeting

 

Organisation: Sebastian Käppler (FAU/ Pattern Recognition Lab)

Talk: Physics-based and statistical features for detecting image manipulations

Speaker: Dr. Christian Riess (FAU)

Place: MPL / Large seminar room (*429/435)

Abstract:

Digital images are now captured anywhere, anywhen, by anyone. For several businesses, e.g., media networks and insurance companies, it is crucial to know whether an image is original, i.e., proof for an event, or manipulated.
In this talk, we will review landmark methods for determining authenticity of an image, including work performed at our lab.

Monday 25. January 2016

IMPRS monthly meeting

 

Organisation: Sivaraman Subramanian (MPL/ Vollmer Lab)

Talk: Conformational Dynamics of Single Enzymes and Biomolecules

Speaker: Dr. Michael Schlierf (Center for Molecular Bioengineering, TU Dresden)

Place: MPL / Seminar room, building 26 (*408)

Abstract:

Over the past decade, numerous single-molecule techniques have become available to study biological molecules. In particular, the observation of conformational changes within these biomolecules or during interactions have become directly accessible. Here, I will present how we develop and apply single-molecule techniques to characterize molecular machines. I will introduce farFRET, a technique to observe large conformational changes, and how we use single-molecule FRET to study membrane protein folding and protein-DNA interactions.

Monday 18. January 2016

IMPRS soft skill course
"Career Building"

 

Teacher: Dr Dennis Fink (mediomix)

Place: Large seminar room of MPL (*429/435)

Participation: Only registered IMPRS students

Thursday 03. December 2015

IMPRS alumni talk

 

Talk about "real life" experiences by: Dr Marta Ziemienczuk (former IMPRS PhD student in Russell Division)

Place: MPL / Large seminar room (*435)

Thursday 03. December 2015

IMPRS monthly meeting

 

Organisation: Martin Finger (MPL/ Russell Division)

Talk: Optical manipulation of biological cells using ultrashort laser pulses and plasmonic gold nanoparticles

Speaker: Dr Maria Leilani Torres (Institute for Quantum Optics, Biomedical Optics Group, Leibniz University Hannover)

Place: MPL / Large seminar room (*435)

Abstract:

This talk will provide a broad overview on cell manipulation using focused pulsed lasers and laser interaction with gold nanoparticles. Several chemical or physical techniques have been previously developed to deliver extracellular biologically relevant molecules to living cells. However, cell specific targeting or high-throughput delivery while maintaining cell viability has remained a challenge.  Laser poration of mammalian cells has recently emerged as an effective means to create transient and sub-micron-sized disruptions on the cell membrane. This light-tissue interaction mechanism depends on the pulse duration and wavelength of light. To address cell-specific targeting, a tightly focused femtosecond laser has been used to transfect single cells such as primary neurons and embryonic stem cells. In order to treat thousands of cells, the interaction of gold nanoparticles with pulsed lasers was utilized for high-throughput cell poration but with localized targeting. As an example, endosomal membranes can be precisely disrupted enabling the intracellular release of molecules within the cytoplasm. Overall these studies demonstrate the effectiveness of pulsed lasers and its interaction with gold nanoparticles for targeted cell disruption and transfection.