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Illustration Terahertz spectroscopy and imaging

The THz band is located between the infrared and microwave domains and comprised typically between 100 GHz and 30 THz. This electromagnetic domain has been relatively less studied than others because of the lack of efficient generation sources and sensitive detection systems. The emergence of low cost and compact ultrashort lasers, that permits the generation of THz waves, is changing this situation.

Besides, the properties of THz waves like its non-ionizing behaviour, capacity to penetrate various materials, spectral signature of most molecules…, makes this technology particularly interesting for non-destructive testing applications.


Multitel proposes :

  • Characterization (imagery and spectroscopy) of different samples in the  terahertz band.
  • Development of femtoseconde laser sources pour THz generation.

Femtosecond laser at 1.55 µm developped by MultitelExample of a 1.55 µm femtoseconde laser developed by Multitel



  • Possibility to cover a spectrum from 0.1 to 6 THz.
  • Materials characterization (absorption or refractive index in the THz band for instance)
  • Thickness measurment


  • Intensity mapping
  • Phase mapping
  • Multi-spectral imaging

Example of characteristics of laser sources developed by Multitel for THz generation:

  • 70 fs at 1550 nm
  • 100 mW average power at 50 MHz repetition rate
  • All-in-fibre configuration, compact, stable and reliable


Fibre coupled TDS THz system
Fibre coupled TDS THz system


THz CW imaging system
CW THz imaging system

Properties of THz radiations

  • Non ionizing, non-invasive et non destructive
  • Low absorption from many materials (paper, plastics, wood, textiles)
  • High absorption from polar molecules (like water for instance)
  • High reflexion onto metallic surfaces
  • Different THz signatures exist for many materials (Pharmaceutical compound, chemical elements, pollutants, plastics…

Application fields

  • Non destructive materials evaluation
  • Thin films characterization
  • Pharmaceutical components elaboration and control
  • Recycling
  • Control of manufacturing processes
  • Security
  • Food industry
  • Biomedical,…


Honeycomb composites THz imaging
THz Image of an honeycomb composite structure
Non destructive inspection of pharmaceutical tablet
Non destructive inspection of pharmaceutical tablet

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