High‐speed scanning by dual feedback control in SNOM/AFM

Abstract

SummaryWe have developed a high-speed scanning near-®eld optical microscope (SNOM)/atomic force microscope (AFM) system including dual feedback controllers. The system includes an additional piezoelectric actuator with fast response in the z direction and a correction circuit to eliminate unnecessary components from the feedback signal. From the measurement of a patterned chromium layer of 2´2 mm 2 checks on a quartz glass plate, we con®rmed that our system had more effective feedback control and faster scanning than current SNOM/AFM systems that use only a piezo-tube. The scanning speed of the present system was estimated to be about ®ve times faster than that of current SNOM/AFM systems.

Methods in Modern Biophysics

“…Tunneling current and feedback voltage are a measure of surface morphology and composition (Binnig et al, 1982a(Binnig et al, , l982b, 1983Binnig and Rohrer, 1987) Electrical l conduction Tunneling of electrons \ \:: through vacuum or air~ . , also known as NSOMs, utilize a light source with a diameter smaller than the wavelength of the light (Synge, 1928;Ash and Nicholls, 1972;Pohl et al, 1984;Betzig et al, 1986Betzig et al, , 1991Betzig et al, , 1992Toledo-Crow et al, 1992;Williamson et al, 1998;Egawa et al, 1999;Heimel et al, 2001). ::: STM images of a 1: 1 mixture of K344C cytochrome P450cam I putidaredoxin adsorbed on gold (111) showed a regular array of pairs of the two proteins .…”

Fuzzy logic scheme for tip-sample distance control for a low cost near field optical microscope

“…This arrangement allows the system to use both technologies; as a consequence the outcome configuration built with a dual feedback control. This scheme makes the system capable to receive optical and physical information [6].…”

Fast contact-mode atomic force microscopy on biological specimen by model-based control

“…For scanning larger samples the vertical bandwidth of the AFM has been increased by introducing additional high-frequency piezo segments to the probing tip [10][11][12] or to the piezo scanner [13,14]. Due to the limited range of the fast Zpiezo, both actuators have to be used in a nested feedback loop to compensate the cantilever deflection [15] when scanning.…”