Near diffraction limited mid-IR spectromicroscopy using frequency upconversion

Nicolai Højer Sanders, Jeppe Seidelin Dam, Peter Tidemand-Lichtenberg, Christian Pedersen

Research output: Chapter in Book/Report/Conference proceedingArticle in proceedingsResearchpeer-review


Mid-infrared microscopy and spectroscopy is interesting due to its medical, biological and chemical applications. Spectromicroscopy can be used for histopathology, sample analysis and diagnosis. The ability to do spectromicroscopy in the 2.5 to 4.5 μm wavelength range where many organic molecules have their fundamental vibrations, with the addition of sufficient spectroscopic resolution to resolve these bands, cane.g.potentially allow for diagnostics without the need for staining of the sample. On a longer timeframe, mid-IR spectromicroscopy has the potential for in-vivo diagnostics, combining morphological and spectral imaging. Recent developments in nonlinear frequency upconversion, have demonstrated the potential to perform both imaging and spectroscopy in the mid-IR range at unparalleled low levels of illumination, the low upconversion detector noise being orders of magnitude below competing technologies. With these applications in mind, we have incorporated microscopy optics into an image upconversion system, achieving near diffraction limited spatial resolution in the 3 μm range. Spectroscopic information is further acquired by appropriate control of the phase match condition of the upconversion process. Multispectral images for a region of interest can be obtained by XY-scanning this region of interest within the field of view of the mid-IR upconversion system. Thus, the whole region of interest can be imaged with all available converter wavelengths, and the spectral representation becomes equal for all points in the image. In addition, the range of converted/imaged wavelengths can be tuned continuously by changing the temperature of the crystal, or discretely by using a different poling channel in the PPLN crystal.
Original languageEnglish
Title of host publicationProceedings of SPIE
Number of pages6
PublisherSPIE - International Society for Optical Engineering
Publication date2014
Publication statusPublished - 2014
EventSPIE Photonics West : Nonlinear Frequency Generation and Conversion: Materials, Devices, and Applications XIII - San Francisco, California, United States
Duration: 1 Feb 20146 Feb 2014


ConferenceSPIE Photonics West : Nonlinear Frequency Generation and Conversion: Materials, Devices, and Applications XIII
CountryUnited States
CitySan Francisco, California


  • Infrar ed mic r oscopy
  • Nonlinear frequency conversion
  • Diode lasers

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