What is QPDI

Vero is a next-generation AFM from Oxford Instruments Asylum Research. Building on its flagship Cypher AFM platform, Vero is the first commercial AFM to use a patented Quadrature Phase Differential Interferometry (QPDI) detector to provide unprecedented performance without compromise in terms of accuracy, range, and noise. 

In this technical note, we will review:

• The basic principles of QPDI design
• How this new detector eliminates cross talk between the vertical and in-plane forces
• How the QPDI detector improves measurement sensitivity and accurately calibrates stiffness and tip displacement