Logo der Physikalisch-Technischen Bundesanstalt

Farfield Fourier Transform Infrared (FTIR)-Microspectroscopy


FTIR-Microspectroscopy enables a non-invasive analysis and identification of chemical and biological compounds. It covers a range of techniques, either based on absorption or transmission spectroscopy of molecules. It also enables spatially resolved structural characterization using phonon modes in solid state samples, as well as the contactless electrical characterization of electronic materials. A common laboratory instrument that uses this technique is a Fourier transform infrared (FTIR) spectrometer. The infrared portion of the electromagnetic spectrum is usually divided into three regions; the near-, mid- and far- infrared, named according to their relation to the visible spectrum. The higher-energy near-IR, approximately 14000 – 4000 cm−1 (0.8 – 2.5 μm) can excite overtone or harmonic vibrations. The mid-infrared, approximately 4000 – 400 cm−1 (2.5 – 25 μm) may be used to study the fundamental vibrations and associated rotational-vibrational structure, and is therefore also called fingerprint spectral window. The far-infrared, approximately 400 – 10 cm−1 (25 – 1000 μm), lying adjacent to the microwave region, has low energy and may be used for rotational spectroscopy. The high brilliance and the broad band of the synchrotron radiation spectrum are particularly favourable for spectroscopic measurements at high spatial resolution [1].


  • Determination of the dielectric function of solid state and liquid sample systems
  • Surface analysis- contamination control, chemical modification
  • Characterization of biological samples (e.g. eukaryotic cells, parasites, viruses, aerosols)
  • Studies on protein dynamics, molecular interactions, conformational changes

Technical Specifications

FTIR spectrometer

  • Vertex80v (Bruker Optics), 0.07 cm-1 max. spectral resolution
  • FTIR microscope (Hyperion3000, Bruker Optics): 4x Vis, 15× IR and 36× Cassegrain objectives, 20x ATR objective, 15x GIR objective
  • Motorized Micrometer sample stage and different sample holders (10° DRIFT unit, variable angle/polarizer reflection unit)
  • Temperature-controlled demountable liquid flow cell (Harrick Scientific)
  • Heating and Cooling stage (Bruker Optics)
  • AquaSpec flow through cell (Bruker Optics)
  • Bio ATR II cell (Bruker Optics)
  • Helium CF Cryostat (Oxford Instruments)
  • Customized, temperature controlled liquid sample cell for diluted organics

Radiation sources

  • Synchrotron radiation from the Metrology Light Source (600 nm – 7 mm) [2]
  • Tungsten-Arc: (1 µm – 9 µm)
  • Globar: (5 µm – 1000 µm)
  • Hg-Arc: (70 µm – 2500 µm)

Detectors of the Vertex80v spectrometer

  • NIR (InSb , CaF2) SNR: 2650 (5600 cm-1 – 6000 cm-1)
  • MIR (MCT (micro), KBr) SNR: 2118 (2100 cm-1 – 2200 cm-1)
  • MIR (DLaTGS, KBr) SNR: 9163 (2100 cm-1 – 2200 cm-1)

Detectors of the Hyperion3000 microscope

  • LN2 MCT Detector (600 cm-1 – 12000 cm-1)
  • LN2 FPA (Focal plane array) detector 128×128 elements (870 cm-1 – 4500 cm-1)
  • LHe Si Bolometer (5 cm-1 – 700 cm-1)

Research Topics

Using FTIR microspectroscopy the group performs fundamental metrology research and supports the development of key technologies, in particular biotechnological assessment methods. Ongoing specific research topics are:

  • Chemical metrology tools for manufacturing advanced biomaterials in the medical device industry (EMRP Q-AIMDS)
  • Characterization of micro-and nanoscaled inorganic/organic biodiagnostic components that can be exposed to biological systems (tissues, cells) [3]
  • IR spectroscopy of wafer-scale Graphene to be used as quantum standard
  • Contactless thermography [4]
  • Food chemistry