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On-chip absorption spectrometer


This on-chip optofluidic array with organic lasers is ideal for rapid on-site investigation of any analyte that absorbs (itself or its products of a specific detection reaction) in the visible (and near IR) spectrum, just like the components of blood.
In combination with a previously developed lamination process, this makes it possible to offer an extremely compact and robust point-of-care diagnostics chip simply and cost-effectively. Application areas such as food or environmental analysis can also benefit.


When using spectrometers, it is essential to know the light intensity in front of and behind the substance under examination in order to precisely determine the absorbed light. Beam splitters are generally used for this purpose, which split off a fraction of the light beam for a reference measurement.


By using filters and beam splitters, conventional spectrometers are comparatively large and of complex design.


The invention presented here uses organic lasers in combination with microfluidic channels directly on-chip to realize an elegant solution for a spectrometer without beam splitter and beam guidance. The resulting reduction in the number of components used also makes the spectrometer much more robust and easier to handle than conventional devices.
The figure shows an array of nine organic lasers (DFB lasers), each emitting light at a specific wavelength. A liquid flowing through the underlying microchannels can accordingly be examined for its absorption behavior with respect to each of the wavelengths used. The second beam direction of the lasers serves as a reference signal.
The analysis system can be implemented cost-effectively for any wavelength of visible light as well as in the near infrared (NIR) – with a spectral width of only 1 nm. Moreover, the materials used to make organic DFB lasers and other structures are non-toxic and can therefore be disposed of without any restrictions.

Schematic diagram of an optofluidic analysis system [Fig: Karlsruhe University of Applied Sciences].
Schematic diagram of an optofluidic analysis system [Fig: Karlsruhe University of Applied Sciences].


  • Universal and robust base unit
  • Disposable cartridges for specific analytes
  • For any wavelength in the visible and NIR
  • Multiple wavelengths per channel and analyte
  • Simple and cost-effective production
  • No filters or beam splitters necessary


Optofluidic on-chip absorption spectroscopy has a wide range of applications, such as product monitoring in the chemical industry, pollutant detection in environmental analysis or blood analysis in medicine. Particularly in medicine, such systems offer ideal conditions for point-of-care diagnostics, such as analyses of blood directly in an ambulance.

Find out more

Sebastian Morain, Jörg Knyrim, Martin Reufer, Christian Karnutsch:
"Optically Pumped Organic Lasers for Microfluidic On-Chip Absorption Spectroscopy",
IEEE WORKSHOP| June, 8th -9th 2017, Mülheim an der Ruhr,

Passt wie angegossen: Laminationsverfahren für die Optofluidische On-Chip-Absorptionsspektroskopie
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Mini-Blutanalyse mit Laserlicht (BANSAI) bekommt Forschungspreis 2019!
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Anne Böse, M.Sc.
Ettlinger Straße 25
76137 Karlsruhe | Germany
Phone +49 721-79004-0
boese(at) |
Development Status
Proof of concept / TRL3
Patent Situation
DE pending
US pending
Reference ID
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