A Novel Non-Raster Scan Method for AFM Imaging

Author(s):  
Nastaran Nikooienejad ◽  
Mohammad Maroufi ◽  
S. O. Reza Moheimani

We report a new non-raster scan method based on a rosette pattern for high-speed atomic force microscopy (AFM). In this method, the lateral axes of the scanner are driven by the sum of two sinusoids with identical amplitudes and different frequencies. We formulate the problem so as to generate the rosette pattern and calculate scan parameters and resolution. To achieve high performance tracking, a controller is designed based on the internal model principle. The controller includes the dynamic modes of the reference signals and higher harmonics to cope with the system nonlinearities. We conduct an experiment employing the proposed method and a two degree of freedom microelectromechanical system nanopositioner to scan a circular-shaped area with a diameter of 6μm in 0.2 sec. The steady state tracking error is less than 4.48nm, i.e. only 9% of the selected resolution. AFM scanning is performed in contact mode constant height and high quality images are obtained.

Sensors ◽  
2021 ◽  
Vol 21 (2) ◽  
pp. 362
Author(s):  
Luke Oduor Otieno ◽  
Bernard Ouma Alunda ◽  
Jaehyun Kim ◽  
Yong Joong Lee

A high-speed atomic force microscope (HS-AFM) requires a specialized set of hardware and software and therefore improving video-rate HS-AFMs for general applications is an ongoing process. To improve the imaging rate of an AFM, all components have to be carefully redesigned since the slowest component determines the overall bandwidth of the instrument. In this work, we present a design of a compact HS-AFM scan-head featuring minimal loading on the Z-scanner. Using a custom-programmed controller and a high-speed lateral scanner, we demonstrate its working by obtaining topographic images of Blu-ray disk data tracks in contact- and tapping-modes. Images acquired using a contact-mode cantilever with a natural frequency of 60 kHz in constant deflection mode show good tracking of topography at 400 Hz. In constant height mode, tracking of topography is demonstrated at rates up to 1.9 kHz for the scan size of 1μm×1μm with 100×100 pixels.


2009 ◽  
Vol 97 (5) ◽  
pp. 1354-1361 ◽  
Author(s):  
Ignacio Casuso ◽  
Noriyuki Kodera ◽  
Christian Le Grimellec ◽  
Toshio Ando ◽  
Simon Scheuring

2013 ◽  
Vol 6 (7) ◽  
pp. 075201 ◽  
Author(s):  
Jianyong Zhao ◽  
Wei Cai ◽  
Guangyi Shang ◽  
Junen Yao

2018 ◽  
Vol 9 ◽  
pp. 1844-1855 ◽  
Author(s):  
Kazuki Miyata ◽  
Takeshi Fukuma

A phase-locked loop (PLL) circuit is the central component of frequency modulation atomic force microscopy (FM-AFM). However, its response speed is often insufficient, and limits the FM-AFM imaging speed. To overcome this issue, we propose a PLL design that enables high-speed FM-AFM. We discuss the main problems with the conventional PLL design and their possible solutions. In the conventional design, a low-pass filter with relatively high latency is used in the phase feedback loop, leading to a slow response of the PLL. In the proposed design, a phase detector with a low-latency high-pass filter is located outside the phase feedback loop, while a subtraction-based phase comparator with negligible latency is located inside the loop. This design minimizes the latency within the phase feedback loop and significantly improves the PLL response speed. In addition, we implemented PLLs with the conventional and proposed designs in the same field programmable gate array chip and quantitatively compared their performances. The results demonstrate that the performance of the proposed PLL is superior to that of the conventional PLL: 165 kHz bandwidth and 3.2 μs latency in water. Using this setup, we performed FM-AFM imaging of calcite dissolution in water at 0.5 s/frame with true atomic resolution. The high-speed and high-resolution imaging capabilities of the proposed design will enable a wide range of studies to be conducted on various atomic-scale dynamic phenomena at solid–liquid interfaces.


2021 ◽  
Vol 9 (4) ◽  
pp. 680
Author(s):  
Christopher T. Evans ◽  
Sara J. Baldock ◽  
John G. Hardy ◽  
Oliver Payton ◽  
Loren Picco ◽  
...  

Suitable immobilisation of microorganisms and single cells is key for high-resolution topographical imaging and study of mechanical properties with atomic force microscopy (AFM) under physiologically relevant conditions. Sample preparation techniques must be able to withstand the forces exerted by the Z range-limited cantilever tip, and not negatively affect the sample surface for data acquisition. Here, we describe an inherently flexible methodology, utilising the high-resolution three-dimensional based printing technique of multiphoton polymerisation to rapidly generate bespoke arrays for cellular AFM analysis. As an example, we present data collected from live Emiliania huxleyi cells, unicellular microalgae, imaged by contact mode High-Speed Atomic Force Microscopy (HS-AFM), including one cell that was imaged continuously for over 90 min.


2012 ◽  
Vol 83 (8) ◽  
pp. 083710 ◽  
Author(s):  
O. D. Payton ◽  
L. Picco ◽  
M. J. Miles ◽  
M. E. Homer ◽  
A. R. Champneys

2012 ◽  
Vol 516 ◽  
pp. 396-401
Author(s):  
Itsuhachi Ishisaki ◽  
Yuya Ohashi ◽  
Tatsuo Ushiki ◽  
Futoshi Iwata

We developed a real-time nanomanipulation system based on high-speed atomic force microscopy (HS-AFM). During manipulation, the operation of the manipulation is momentarily interrupted for a very short time for high-speed imaging; thus, the topographical image of the fabricated surface is periodically updated during the manipulation. By using a high-speed imaging technique, the interrupting time could be much reduced during the manipulation; as a result, the operator almost does not notice the blink time of the interruption for imaging during the manipulation. As for the high-speed imaging technique, we employed a contact-mode HS-AFM to obtain topographic information through the instantaneous deflection of the cantilever during high-speed scanning. By using a share motion PZT scanner, the surface could be imaged with a frame rate of several fps. Furthermore, the high-speed AFM was coupled with a haptic device for human interfacing. By using the system, the operator can move the AFM probe into any position on the surface and feel the response from the surface during manipulation. As a demonstration of the system, nanofabrication under real-time monitoring was performed. This system would be very useful for real-time nanomanipulation and fabrication of sample surfaces.


2003 ◽  
Vol 11 (2) ◽  
pp. 42-43
Author(s):  
John T. Woodward

What is the best cantilever for intermittent contact mode (often called Tapping Mode™) atomic force microscope (AFM) imaging under water? This is a question I hear often and one that recently generated some interesting discussion on an AFM newsgroup (more on the newsgroup below). The ability of the AFM to image samples En physiologically relevant environments has made it a popular technique in the biological sciences. However, because scanning the AFM tip in contact mode easily perturbs many biological samples, it was the advent of intermittent contact modes that lead to AFM's widespread use in biology.


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