Local infrared microspectroscopy with subwavelength spatial resolution with an atomic force microscope tip used as a photothermal sensor

Opt Lett. 2005 Sep 15;30(18):2388-90. doi: 10.1364/ol.30.002388.


We describe a new method of infrared microspectroscopy. It is intended for performing chemical mapping of various objects with subwavelength lateral resolution by using the infrared vibrational signature characterizing different molecular species. We use the photothermal expansion effect, detected by an atomic force microscope tip, probing the local transient deformation induced by an infrared pulsed laser tuned at a sample absorbing wavelength. We show that this new tool opens the way for measuring and identifying spectroscopic contrasts not accessible by far-field or near-field optical methods and with a subwavelength lateral resolution.

Publication types

  • Evaluation Study

MeSH terms

  • Escherichia coli / chemistry*
  • Escherichia coli / ultrastructure*
  • Image Enhancement / instrumentation
  • Image Enhancement / methods*
  • Microscopy, Atomic Force / instrumentation
  • Microscopy, Atomic Force / methods*
  • Spectrophotometry, Infrared / instrumentation
  • Spectrophotometry, Infrared / methods*
  • Thermography / instrumentation
  • Thermography / methods*
  • Transducers