Resonant difference-frequency atomic force ultrasonic microscope

US7845215B2 · kind B2 · utility

Assignee

• The United States of America as represented by the Administrator of the National Aeronautics and Space Administration · US

Inventors

• John H. Cantrell · Williamsburg, US
• Sean Cantrell · Williamsburg, US

Key dates

• Filing date: Aug 24, 2007
• Grant date: Dec 7, 2010
• Expiry date: Feb 3, 2029

Classification

• Technology area (CPC G): Physics
• CPC primary: G01Q60/32
• WIPO field: Measurement
• WIPO sector: Instruments

Abstract

A scanning probe microscope and methodology called resonant difference-frequency atomic force ultrasonic microscopy (RDF-AFUM), employs an ultrasonic wave launched from the bottom of a sample while the cantilever of an atomic force microscope, driven at a frequency differing from the ultrasonic frequency by one of the contact resonance frequencies of the cantilever, engages the sample top surface. The nonlinear mixing of the oscillating cantilever and the ultrasonic wave in the region defined by the cantilever tip-sample surface interaction force generates difference-frequency oscillations at the cantilever contact resonance. The resonance-enhanced difference-frequency signals are used to create images of nanoscale near-surface and subsurface features.