The optical lever detection method has been widely used to detect the cantilever deflection in atomic force microscope
(AFM) due to its simple mechanism and high sensitivity. The deflection detection of very small cantilever is a key and
difficult issue in the development of a high-speed AFM. In this paper, a specially designed optical beam deflection
detection system based on an aspheric lens is presented. The aspheric lens is fixed on an adjustable metal tube above the
cantilever to focus the laser beam with a small spot. Two laser line beamsplitter cubes are installed symmetrically and
oppositely over the aspheric lens with separately mounting a diode laser and a position sensitive detector (PSD) on two
translation stages at the same height. The collimated laser beam is reflected down by one cube and focused by the
aspheric lens at an off-centered position. The focused beam is then incident upon the cantilever and reflected back onto
the opposite off-centered position. Change in the reflection angle caused by the cantilever deflection results in a parallel
shift of the outgoing laser beam after the aspheric lens. The laser beam is finally reflected onto the PSD by the other
cube. Experimental results show that the laser beam can be focused with a spot of less than 16 μm in diameter. With
above system, the deflection detection of the small cantilever can be realized, which meets the requirement for the use in
a high-speed AFM.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
INSTITUTIONAL Select your institution to access the SPIE Digital Library.
PERSONAL Sign in with your SPIE account to access your personal subscriptions or to use specific features such as save to my library, sign up for alerts, save searches, etc.