How AFM-IR works

A pulsed, tunable infrared laser illuminates the sample under an AFM tip. When the laser is tuned to an absorption band, the sample heats up and expands slightly. The AFM cantilever picks up this tiny, fast expansion as an oscillation. Recording the oscillation amplitude while sweeping the laser wavelength gives a local IR spectrum; scanning at a fixed wavelength gives a chemical map.

TODO: add a simple diagram — upload it to an img/ folder and insert it with ![Description](/img/your-file.png)

Measurement modes

TODO: describe the modes you use and their trade-offs, for example:

  • Contact mode — …
  • Resonance-enhanced — …
  • Tapping mode — …
  • Surface-sensitive — …

Interpreting data: common pitfalls

TODO: this is where your experience matters most. Ideas:

  • Laser power normalisation and background spectra
  • Mechanical contributions vs. true absorption
  • Sample thickness and substrate effects
  • Comparing AFM-IR spectra with bulk FTIR

Practical limits

TODO: spectral range of common lasers, spatial resolution, sample requirements.