The nanoIR1 is designed with a bottom-up laser illumination (in total reflection). The major constraint is the necessity to deposit the sample on ZnSe prims or specific CaF2 windows.
Bottom-up illumination
Two options of IR laser sources :
1. OPO source 4000-1000 cm-1 : non-resonant mode. Sensitivity limit : 50-100 nm size. Spectral resolution 6-8 cm-1
2. QCL source, 1820-1520 cm-1 : resonant enhanced mode. Sensitivity limit : 20 nm. Spectral resolution < 1 cm-1.
Main advantages : 
the laser illumination is very well controlled to enable consistent measurements across the full spectrum the polarization of the light can be rotated to investigate polarization effects in materials optional liquid environment is available for FLUID AFM-IR Ideal for Eucaryotic cells/ polymer/ tissue sectioning Biomolecules aggregates or fibrils (bigger than 20nm)
Constraints : Sample thickness must be less than 1 um on ZnSe prism but any size on CaF2 windows. Sample thickness usually limits the resolution. Works in AFM contact mode requiring good sample to prism adhesion (ZnSe or CaF2)