Wideband low-noise optical beam deflection sensor with photothermal excitation for liquid-environment atomic force microscopy

Wideband low-noise optical beam deflection sensor with photothermal excitation for liquid-environment atomic force microscopy.

I developed a wideband low-noise optical beam deflection sensor with a photothermal cantilever excitation system for liquid-environment atomic force microscopy. The developed sensor has a 10 MHz bandwidth and 4.7 fm/sq.rt.Hz deflection noise density in water. The theoretically limited noise performance (i.e., the noise level limited only by the photodiode shot noise) has been achieved in liquid...

A high frequency sensor for optical beam deflection atomic force microscopy.

We demonstrate a novel electronic readout for quadrant photodiode based optical beam deflection setups. In our readout, the signals used to calculate the deflections remain as currents, instead of undergoing an immediate conversion to voltages. Bipolar current mirrors are used to perform all mathematical operations at the transistor level, including the signal normalizing division. This method ...

Development of liquid-environment frequency modulation atomic force microscope with low noise deflection sensor for cantilevers of various dimensions

We have developed a liquid-environment frequency modulation atomic force microscope FM-AFM with a low noise deflection sensor for a wide range of cantilevers with different dimensions. A simple yet accurate equation describing the theoretical limit of the optical beam deflection method in air and liquid is presented. Based on the equation, we have designed a low noise deflection sensor. Replace...

Sensitivity Analysis of Frequency Response of Atomic Force Microscopy in Liquid Environment on Cantilever's Geometrical Parameters

In this paper, the non-linear dynamic response of rectangular atomic force microscopy in tapping mode is considered. The effect of cantilever’s geometrical parameters (e.g., cantilever length, width, thickness, tip length and the angle between the cantilever and the sample's surface in liquid environment has been studied by taking into account the interaction forces. Results indicate that the r...

Comparison of photothermal and piezoacoustic excitation methods for frequency and phase modulation atomic force microscopy in liquid environments