Nanotechnology World - New Dual AC™ Imaging Mode for Atomic Force Microscopy

New Dual AC™ Imaging Mode for Atomic Force Microscopy

Asylum Research announces an exclusive new imaging mode, Dual AC, that goes beyond conventional phase imaging in measuring the mechanical and chemical properties of samples by employing higher resonance modes of cantilevers. The patent-pending Dual AC Mode is available only on the Asylum Research MFP-3D Atomic Force Microscope.

“Dual AC Mode is a leap forward in characterising materials in both air and liquid,” said Roger Proksch, President of Asylum Research. “Unlike phase imaging which typically requires a choice of setpoint and drive amplitude to maximise the phase contrast, Dual AC shows increased contrast over a much wider range of imaging parameters. It also provides information on the frequency dependent mechanical properties of a surface. Because of the pioneering all-digital nature of our MFP-3D controller, Dual AC Mode was added without any hardware modifications and is available to all current MFP-3D users. It is a perfect example of how going digital allows us to bring cutting edge improvements to our customers without costly hardware upgrades.”

In Dual AC, the cantilever is driven at or near two or more of its resonance frequencies. The cantilever motion is then analysed by two quadrature digital lock-in amplifiers. The output of the lock-ins can be displayed, saved, combined with other signals and used in user-selected feedback loops.

Dual AC mode shows strikingly different contrast from the fundamental amplitude and phase signals that are used in AC imaging mode. In this 10µm scan made of graphite, “A” is the height image, “B” is the fundamental amplitude, “C” is the fundamental phase, and “D” is the second mode (Dual AC) amplitude image. The second mode amplitude shows striking contrast not visible in the other channels.

Dual AC mode shows strikingly different contrast from the fundamental amplitude and phase signals that are used in AC imaging mode. In this the image of a 10 µm scan made of graphite, “A” is the height image, “B” is the fundamental amplitude, “C” is the fundamental phase, and “D” is the second mode (Dual AC) amplitude image. The second mode amplitude shows striking contrast not visible in the other channels.

More information: http://www.asylumresearch.com