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Atomic force microscopy maps surfaces and measures small interactions using a sharp tip attached to a compliant cantilever. In a common modern readout, a laser reflects from the cantilever onto a split photodetector, turning bending into an electrical signal. A scanner moves the tip relative to the sample; feedback can adjust height to maintain a chosen interaction signal. With calibrated stiffness $k$, a small static deflection $\delta$ gives force $F\approx k\delta$. The measured image combines surface geometry, tip geometry and interaction physics, so narrow features can appear broadened. Gerd Binnig, Calvin Quate and Christoph Gerber introduced the instrument in 1986.^[ref] Modern force measurements additionally require calibrated cantilever stiffness.^[ref]

Calvin Quate developed instruments that use mechanical interactions to reveal microscopic structure. His Stanford memorial describes his work on scanning acoustic microscopy and, with Gerd Binnig and Christoph Gerber, atomic force microscopy.^[ref]

Their 1986 atomic-force-microscope paper used a compliant mechanical probe and sensitive displacement detection to measure surface interactions. Its preliminary measurements demonstrated nanometre-scale lateral structure and sub-nanometre vertical sensitivity; the proposed atomic-scale goal and those initial measured resolutions should be distinguished. This instrument-building contribution opened a route to imaging surfaces without requiring a tunnelling current through the specimen.^[ref]

Christoph Gerber helped develop atomic force microscopy with Gerd Binnig and Calvin Quate. Their 1986 paper introduced an instrument that senses probe–sample forces through a compliant cantilever, enabling investigation of electrically insulating surfaces.^[ref]

The mechanical probe makes a small interaction measurable through displacement: in a linear approximation, a cantilever of spring constant $k$ deflecting by $d$ carries force $F=kd$. Gerber's later research includes biochemical cantilever sensors, extending the same transduction principle from surface imaging to detection of molecular interactions.^[ref]