Implementation on a desktop computer of the real time feedback control loop of a scanning probe microscope

Aloisi, Giovanni; Bacci, F.; Carlà, Marcello; Dolci, D.; Lanzi, Leonardo

doi:10.1063/1.2992483

Cited by 11 publications

(3 citation statements)

References 24 publications

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“…29 Probe motion on the three axes was controlled through a digital feedback loop implemented with a software emulated digital signal processor on a standard personal computer. 30 All measurements have been performed on the surface of a clean cleaved mica sheet, about 1 cm × 1 cm, with a varying degree of aging and negatively polarized at about 0.5 V with respect to the probe. Environmental relative humidity (RH) has been kept between 60% and 80%; polarization voltage has been adjusted at the start of every measure in order to obtain a current of about 15 pA during the probe-surface contact.…”

Section: Methodsmentioning

confidence: 99%

Use of scanning probe microscopy to study the evolution of nanometer sized liquid structures

Aloisi

Bacci

Carlà

et al. 2011

Review of Scientific Instruments

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The evolution of the profile of nanometer sized water drops on a mica surface has been studied through hydration scanning probe microscopy. A time range from a few seconds down to a fraction of millisecond after the formation of the drop has been explored. This high time resolution has been obtained by sampling a series of statistically equivalent drops. This approach also avoids any probe interference during the drop evolution process.

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Section: Methodsmentioning

confidence: 99%

Use of scanning probe microscopy to study the evolution of nanometer sized liquid structures

Aloisi

Bacci

Carlà

et al. 2011

Review of Scientific Instruments

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“…This open source package, operating in a Linux environment, has been originally developed for real time control of the feedback of a scanning microscope. [20][21][22] The second channel of the ADC is used to directly sample the f m signal. Acquired data are stored to disk for off-line processing.…”

Section: Methodsmentioning

confidence: 99%

Electron-paramagnetic resonance detection with software time locking

Aloisi

Mannini

Caneschi

et al. 2014

Review of Scientific Instruments

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A setup for electron paramagnetic resonance with narrow band digital detection is described. A low frequency reference tone is added to the radio frequency signal. This reference signal, after digital detection, is used to lock the resonance signal, even in the absence of hardware time locking among the radio frequency generator, the conversion local oscillators, and the sampling stage. Results obtained with 2,2-Diphenyl-1-Pycryl-Hydrazil are presented and discussed.

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“…In 2008, Aloisi et al used computers to develop and implement the functions of the AFM and realized the control of the real-time feedback loop of the scanning probe microscope (SPM). However, using a commercial computer as the AFM control system limits new technology research and performance improvement, and further improvement of the resolution or the scanning speed often requires specially customized modules [ 8 ].…”

Section: Introductionmentioning

confidence: 99%

Measurement and Control System for Atomic Force Microscope Based on Quartz Tuning Fork Self-Induction Probe

et al. 2023

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In this paper, we introduce a low-cost, expansible, and compatible measurement and control system for atomic force microscopes (AFM) based on a quartz tuning fork (QTF) self-sensing probe and frequency modulation, which is mainly composed of an embedded control system and a probe system. The embedded control system is based on a dual-core OMAPL138 microprocessor (DSP + ARM) equipped with 16 channels of a 16-bit high-precision general analog-to-digital converter (ADC) and a 16-bit high-precision general digital-to-analog converter (DAC), six channels of an analog-to-digital converter with a second-order anti-aliasing filter, four channels of a direct digital frequency synthesizer (DDS), a digital input and output (DIO) interface, and other peripherals. The uniqueness of the system hardware lies in the design of a high-precision and low-noise digital—analog hybrid lock-in amplifier (LIA), which is used to detect and track the frequency and phase of the QTF probe response signal. In terms of the system software, a software difference frequency detection method based on a digital signal processor (DSP) is implemented to detect the frequency change caused by the force gradient between the tip and the sample, and the relative error of frequency measurement is less than 3%. For the probe system, a self-sensing probe controller, including an automatic gain control (AGC) self-excitation circuit, is designed for a homemade balanced QTF self-sensing probe with a high quality factor (Q value) in an atmospheric environment. We measured the quality factor (Q value) of the balanced QTF self-sensing probes with different lengths of tungsten tips and successfully realized AFM topography imaging with a tungsten-tip QTF probe 3 mm in length. The results show that the QTF-based self-sensing probe and the developed AFM measurement and control system can obtain high quality surface topography scanning images in an atmospheric environment.

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Implementation on a desktop computer of the real time feedback control loop of a scanning probe microscope

Cited by 11 publications

References 24 publications

Use of scanning probe microscopy to study the evolution of nanometer sized liquid structures

Use of scanning probe microscopy to study the evolution of nanometer sized liquid structures

Electron-paramagnetic resonance detection with software time locking

Measurement and Control System for Atomic Force Microscope Based on Quartz Tuning Fork Self-Induction Probe

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