Direct and alignment-insensitive measurement of cantilever curvature

TL;DR

This paper presents a novel optical method using Fresnel diffraction patterns for simultaneous, alignment-insensitive measurement of cantilever deflections and curvatures, suitable for large arrays and biosensor applications.

Contribution

The authors introduce an analytical and experimental technique that measures cantilever shape and tilt without precise alignment, enabling multi-cantilever analysis in various environments.

Findings

Works in liquid and air environments

Applicable to large cantilever arrays

Provides absolute shape calibration

Abstract

We analytically derive and experimentally demonstrate a method for the simultaneous measurement of deflection for large arrays of cantilevers. The Fresnel diffraction patterns of a cantilever independently reveals tilt, curvature, cubic and higher order bending of the cantilever. It provides a calibrated absolute measurement of the polynomial coefficients describing the cantilever shape, without careful alignment and could be applied to several cantilevers simultaneously with no added complexity. We show that the method is easily implemented, works in both liquid mediums and in air, for a broad range of displacements and is especially suited to the requirements for multi-marker biosensors.