Interpreting MP-SPR and ellipsometry results

Ellipsometry and Multi-Parametric Surface Plasmon Resonance (MP-SPR) can both determine thickness OR refractive index.

Spectroscopic ellipsometry (SE) and MP-SPR can both determine thickness AND refractive index.

The main difference comes from the samples that the techniques can work with, which is given by the optical set-up of the two.



  • MP-SPR measures from the back of the sample (the collected light does not travel through the sample or the air/liquid environment)
  • MP-SPR uses simple substrates with at least one plasmonic layer
  • MP-SPR utilizes the plasmon, which enhances sensitivity of the method especially for metals
  • MP-SPR can determine both d and n
  • MP-SPR is suited for measurements in gas or liquids
  • 2 channels enable easy referencing (channel volume is 1 µL)


  • In ellipsometry, the collected light travels through the sample and its air/liquid environment
  • Ellipsometry works the best with very flat and very well reflecting substrates
  • In traditional ellipsometry, the optical parameters d or n need to be known
  • Ellipsometry is well suited for measurements in air
  • There is only 1 channel (channel volume is 1 mL, which makes biological experiments too expensive and without a reference channel difficult to validate)


mp-spr_ellipsometry_m.pngThe difference in optical set-up of Multi-Parametric Surface Plasmon Resonance and Ellipsometry.