THz Spectroscopy

The characteristic properties of Terahertz waves (1012 Hz), between optical infrared and electronical microwave frequencies explore significant application possibilities for electronic and optoelectronic components for broadband communication and THz analysis.
Traditionally the THz frequency range is covered by heterodyne and incoherent techniques. But their low bandwidth restricts their applications to well defined problems. The rise of ultra short pulsed lasers opened the way for evolvement of extremely flexible and broadband systems in the frequency range from a few GHz up to 35 THz and therefore a much broader application potential.

The projects presented here demonstrate parts of the huge potential of this new technology for applications as well as for basic research. These experiments are based on the Time Domain THz Spectroscopy (TDTS). In these experiments ultra short pulses (<100 fs) from a Ti:Sapphire laser are split into two beams. One is used to generate THz pulses that are focussed onto a sample. The transmitted radiation is then focused to the detector which is switched by the second beam. An adjustable time delay between the two optical beams allows the time-resolved detection of the THz transient. This setup allows the detection of amplitude and phase in a very broadband spectral range. This graph shows a typical time transient and its related power spectrum.
The following short descriptions show examples demonstrating the potential of this technology.

  • DNA Analysis
    Label free detection of the binding state of DNA.
  • THz Modulation
    A combined optical and spatial modulation is used to drastically increase the sensitivity for characterization of thin films.
  • Optical Pump - THz Probe
    The optically excited dynamics in a superconductor sample is observed time-resolved by THz transmission spectroscopy.
  • THz Tomography
    Three-dimensional depth resolved measurement demonstrated for characterization of a ceramic layered sample used for Solid Oxide Fuel Cells (SOFC).

The following System is developed and offered for purchase by AMO GmbH Aachen, Germany. I developed the graphical user interface in Labview (National Instruments).

  • AIXScan
    Description of a data acquisition system based on a fast time delay, which enables high signal/noise ratio and online alignment capabilities.

[Martin Brucherseifer] [About me] [Resume] [SEM / FIB] [Scanning Probe Microscopy] [THz Spectroscopy] [DNA Analysis] [THz Modulation] [THz Tomography] [Optical Pump - THz Probe] [AIXScan] [Publications] [Links] [Disclaimer]