Overview
Linear and Nonlinear THz Science
Optical Fibers and Fiber Lasers
Quantum Optics
Soft X-Ray Laser
Ultrafast Molecular Spectroscopy
Last update: 18.10.2017
Linear and Nonlinear THz Science Lab - The Feurer Group
Linear and Nonlinear THz Science Lab - The Feurer Group
Plasmonic devices and metamaterials have paved the way towards unprecedented optical phenomena, such as improved focusing, electromagnetic cloaking, enhanced spectroscopic sensitivity, or the implementation of novel optical properties like negative or giant refractive indices. Whereas most experimental studies to date investigate the light distribution in the far-field of such structures, gaining a comprehensive understanding of the underlying mechanisms requires monitoring their near-fields. Due to typical structure dimensions on the wavelength to sub-wavelength scale, however, near-field studies with the required spatial resolution are highly challenging and experiments in the long-wavelength regime can be advantageous. Recently, imaging at terahertz (THz) frequencies proved to be immensely powerful for a detailed investigation of the near-fields around sub-wavelength metallic structures. Based on the coherent emission and detection of single-cycle THz pulses this approach allows measuring all three time-dependent electric fields components with sub-ps temporal and sub-wavelength spatial resolution. In our laboratory we have developed several unique THz near-field imaging tools with which we investigate fundamental building blocks of metamaterials. Most of our findings can be transferred to other spectral regions and help designing new materials with unusual properties and functionalities. Often it is necessary to accurately know the effective material properties of metamaterials, in stationary state as well as dynamically, which is why we develop a time resolved THz ellipsometry setup together with C. Bernhard's group from the University of Fribourg.

If designed appropriately such sub-wavelength metal structures can also be used as efficient antennas focusing incident THz radiation to sub-diffraction limited volumina. Within those, the electric field is enhanced by enormous factors approaching tens of thousands. In the THz regime, field enhancement is of importance due to the present technological limitations in the peak fields obtainable from current THz sources which limits the realization of nonlinear THz experiments. Recently, Seo et al. reported a field enhancement factor approaching 1000 at 0.1 THz using a single 70 nm wide metallic slit. Our COMSOL simulations of other structures show that field enhancements up to several tens of thousands should be feasible, and for fabrication of those structures we have a wonderful collaboration with the PSI Laboratory for Micro- and Nanotechnology. With our newly installed laser system we will approach the 10 to 100 MV/cm field strength regime. When THz pulses come as quasi half-cycle pulses the high electric and magnetic field strengths allow investigating electric and magnetic field-induced switching. Such fields may be considered DC on time scales of up to a few picoseconds, which is ideal for studying charge transfer dynamics under the influence of such high fields. There are myriads of other applications of high THz fields in science and the few examples given here should be sufficient to stimulate our minds.
 
Brügmann, Dr. Michael   Contact  
Portrait Michael Brügmann, Dr.
Division:Laser Physics
Group:Linear and Nonlinear THz Science
Status:Postdoc
 
Das, Dr. Anuradha   Contact  
Portrait Anuradha Das, Dr.
Division:Laser Physics
Group:Linear and Nonlinear THz Science
Status:Postdoc
 
Feurer, Prof. Dr. Thomas   Contact  
Portrait Thomas Feurer, Prof. Dr.
Division:Laser Physics
Group:Linear and Nonlinear THz Science
Status:IAP Director,
Head of division,
Head of group
 
Frey, Dr. Hans-Martin   Contact  
Portrait Hans-Martin Frey, Dr.
Division:Laser Physics
Group:Linear and Nonlinear THz Science
Status:Postdoc
 
Gäumann Gregory   Contact  
Portrait Gregory Gäumann
Division:Laser Physics
Group:Linear and Nonlinear THz Science
Status:Ph.D. student
 
Hayati Mozhgan   Contact  
Portrait Mozhgan Hayati
Division:Laser Physics
Group:Linear and Nonlinear THz Science
Status:Ph.D. student
 
Heidt, Dr. Alexander   Contact  
Portrait Alexander Heidt, Dr.
Division:Laser Physics
Group:Linear and Nonlinear THz Science
Status:Postdoc
 
Kim, Dr. Hyunjoo   Contact  
Portrait Hyunjoo Kim, Dr.
Division:Laser Physics
Group:Linear and Nonlinear THz Science
Status:Postdoc
 
Ollmann, Dr. Zoltan   Contact  
Portrait Zoltan Ollmann, Dr.
Division:Laser Physics
Group:Linear and Nonlinear THz Science
Status:Postdoc
 
Rohwer, Dr. Egmont   Contact  
Portrait Egmont Rohwer, Dr.
Division:Laser Physics
Group:Linear and Nonlinear THz Science
Status:Postdoc
 
Roille Stephen   Contact  
Division:Laser Physics
Group:Linear and Nonlinear THz Science
Status:Ph.D. student
 
Schweizer Tobias   Contact  
Portrait Tobias Schweizer
Division:Laser Physics
Group:Linear and Nonlinear THz Science
Status:Ph.D. student
 
Siegrist Michael   Contact  
Portrait Michael Siegrist
Division:Laser Physics
Group:Linear and Nonlinear THz Science
Status:Ph.D. student
 
Tarkeshian, Dr. Roxana   Contact  
Portrait Roxana Tarkeshian, Dr.
Division:Laser Physics
Group:Linear and Nonlinear THz Science
Status:Postdoc
 
Valzania Lorenzo   Contact  
Division:Laser Physics
Group:Linear and Nonlinear THz Science
Status:Ph.D. student