Determine layer unique refractive index and thickness with MP-SPR
Application Note #128
Illustration of the two wavelength analysis principle. Black and orange line are RI – d continuum answers for both of the wavelengths. Dashed line is sifted curve based on the dRI/dλ value, which enables a unique solution for the thickness and RI.
Multi-Parametric Surface Plasmon Resonance (MP-SPR) can be used to determine unique thickness and refractive index (RI) of ultrathin films without prior knowledge of the RI or the thickness of the layer. Polyelectrolyte multilayer was measured using MP-SPR two wavelength method and analysed by LayerSolver™ software module. Thickness of 5 bilayers was found to be 16.8 nm and RI 1.48 at 785 nm.
Recommended instrument for this application
Further reading
- If you are interested in reading more about in situ and ex situ methods and measurements, see AN#139 and AN#150.
- Do you want to find out how to calculate thickness out of MP-SPR measurements? Click here
- Do you want to see MP-SPR instruments comparison? Click here