design for afm demonstration kevin d. mccarthy 9/28/05

Design for AFM demonstration

Kevin D. McCarthy

9/28/05

What is AFM and why is it so clever?

Atomic force microscope

photodetector

k ≈ 0.1 N/m

AFM: Atomic Force Microscope

Atomic force microscope, deflected

photodetector

k ≈ 0.1 N/m

Feedback loop

How it traces surface…

xVpiezo

photodetector

k ≈ 0.1 N/m

Optical lever’s sensitivity meansnN forces can be controllably exerted…

Design for class-room scale demo of AFM imaging mechanism…

Z axis motion…

Laser pointer

mirror

“photo-detector” screen

•Wheeled assembly can be rolled over books or other ~1 inch obstacles, while operator tries to maintain dot position on photo-detector screen.

•An assistant can be continuously recording (strip-chart style) the ‘z piezo’ reading vs. x (horizontal position)

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