scholarly journals Understanding interferometry for micro-cantilever displacement detection

2016 ◽  
Vol 7 ◽  
pp. 841-851 ◽  
Author(s):  
Alexander von Schmidsfeld ◽  
Tobias Nörenberg ◽  
Matthias Temmen ◽  
Michael Reichling

Interferometric displacement detection in a cantilever-based non-contact atomic force microscope (NC-AFM) operated in ultra-high vacuum is demonstrated for the Michelson and Fabry–Pérot modes of operation. Each mode is addressed by appropriately adjusting the distance between the fiber end delivering and collecting light and a highly reflective micro-cantilever, both together forming the interferometric cavity. For a precise measurement of the cantilever displacement, the relative positioning of fiber and cantilever is of critical importance. We describe a systematic approach for accurate alignment as well as the implications of deficient fiber–cantilever configurations. In the Fabry–Pérot regime, the displacement noise spectral density strongly decreases with decreasing distance between the fiber-end and the cantilever, yielding a noise floor of 24 fm/Hz0.5 under optimum conditions.

2016 ◽  
Vol 87 (7) ◽  
pp. 073702 ◽  
Author(s):  
H. von Allwörden ◽  
K. Ruschmeier ◽  
A. Köhler ◽  
T. Eelbo ◽  
A. Schwarz ◽  
...  

2013 ◽  
Vol 21 (2) ◽  
Author(s):  
M. Mazur ◽  
D. Wojcieszak ◽  
J. Domaradzki ◽  
D. Kaczmarek ◽  
S. Song ◽  
...  

AbstractIn this paper designing, preparation and characterization of multifunctional coatings based on TiO2/SiO2 has been described. TiO2 was used as a high index material, whereas SiO2 was used as a low index material. Multilayers were deposited on microscope slide substrates by microwave assisted reactive magnetron sputtering process. Multilayer design was optimized for residual reflection of about 3% in visible spectrum (450–800 nm). As a top layer, TiO2 with a fixed thickness of 10 nm as a protective film was deposited. Based on transmittance and reflectance spectra, refractive indexes of TiO2 and SiO2 single layers were calculated. Ultra high vacuum atomic force microscope was used to characterize the surface properties of TiO2/SiO2 multilayer. Surface morphology revealed densely packed structure with grains of about 30 nm in size. Prepared samples were also investigated by nanoindentation to evaluate their protective performance against external hazards. Therefore, the hardness of the thin films was measured and it was equal to 9.34 GPa. Additionally, contact angle of prepared coatings has been measured to assess the wetting properties of the multilayer surface.


2012 ◽  
Vol 3 ◽  
pp. 52-56 ◽  
Author(s):  
Woo-Kyung Lee ◽  
Minchul Yang ◽  
Arnaldo R Laracuente ◽  
William P King ◽  
Lloyd J Whitman ◽  
...  

Polymer nanostructures were directly written onto substrates in ultra-high vacuum. The polymer ink was coated onto atomic force microscope (AFM) probes that could be heated to control the ink viscosity. Then, the ink-coated probes were placed into an ultra-high vacuum (UHV) AFM and used to write polymer nanostructures on surfaces, including surfaces cleaned in UHV. Controlling the writing speed of the tip enabled the control over the number of monolayers of the polymer ink deposited on the surface from a single to tens of monolayers, with higher writing speeds generating thinner polymer nanostructures. Deposition onto silicon oxide-terminated substrates led to polymer chains standing upright on the surface, whereas deposition onto vacuum reconstructed silicon yielded polymer chains aligned along the surface.


2012 ◽  
Vol 1455 ◽  
Author(s):  
Oliver Ochedowski ◽  
Benedict Kleine Bußmann ◽  
Marika Schleberger

ABSTRACTWe have employed atomic force and Kelvin-Probe force microscopy to study graphene sheets exfoliated on TiO2 under the influence of local heating achieved by laser irradiation. Exfoliation and irradiation took place under ambient conditions, the measurements were performed in ultra high vacuum. We show that after irradiation times of 6 min, an increase of the surface potential is observed which indicates a decrease of p-type carrier concentration. We attribute this effect to the removal of adsorbates like water and oxygen. After irradiation times of 12 min our topography images reveal severe structural modifications of graphene. These resemble the nanocrystallite network which form on graphene/SiO2 but after much longer irradiation times. From our results we propose that short laser heating at moderate powers might offer a way to clean graphene without inducing unwanted structural modifications.


Holzforschung ◽  
2007 ◽  
Vol 61 (5) ◽  
pp. 523-527 ◽  
Author(s):  
Lothar Klarhöfer ◽  
Florian Voigts ◽  
Dominik Schwendt ◽  
Burkhard Roos ◽  
Wolfgang Viöl ◽  
...  

Abstract Metastable induced electron spectroscopy (MIES), ultraviolet photoelectron spectroscopy (UPS), X-ray photoelectron spectroscopy (XPS) and atomic force microscopy (AFM) were applied to study the interaction of Ti metal atoms with spruce surfaces. Spruce surfaces were produced by planing splints from a spruce bar. Ti atoms were adsorbed from a metal evaporator under ultra-high vacuum conditions. The amount adsorbed corresponds to 10 monolayer equivalents. Strong interactions between the spruce surface and metals atoms occurred. Impinging Ti atoms were oxidized by the spruce surface. No Ti agglomeration or particle formation was observed. The surface was smoothed by the Ti applied and was completely covered by a titanium oxide film.


Author(s):  
Denis S . Kryuchkov ◽  
Gulnara A. Vishnyakova ◽  
Ksenia Yu. Khabarova ◽  
Konstantin S. Kudeyarov ◽  
Nikita O. Zhadnov ◽  
...  

Here we consider creation of laser systems stabilized by external macroscopic monolithic Fabry – Perot cavities made of single-crystalline silicon operating at cryogenic temperatures. Fundamental thermal noise floor for fractional frequency instability was evaluated with its dependency on cavity’s spacer, mirror’s substrate and coatings material. Silicon cavities with dielectric SiO2 /Ta2 O5 and crystalline GaAs/InGaAs mirror coatings were created, its finesse at room temperatures was investigated. Two ultra-high vacuum optical cryostats were developed. Two ultra-stable laser systems based on cavities with dielectric mirrors were assembled. Comparison scheme via beat signal frequency counting was implemented for the characterization purpose. Different noise sources presenting at assembled systems are considered. Its impact to relative frequency instability of our laser systems is being explored.


Author(s):  
Gregory W. Vogl ◽  
Jon R. Pratt

A new self-excited micro-oscillator is proposed as a velocity reference that could aid the dissemination of nanonewton-level forces that are traceable to the International System of Units (SI). An analog control system is developed to keep the actuation side of the device oscillating sinusoidally with an amplitude that is fairly insensitive to the quality factor. Consequently, the device can be calibrated as a velocity reference in air and used in ultra-high vacuum with a velocity shift of less than one percent. Hence, the calibrated micro-oscillator could be used with electrostatic forces to calibrate cantilevers used for atomic force microscopy (AFM) as SI-traceable force transducers. Furthermore, the calibrated micro-oscillator could potentially be used as an AFM sensor to achieve atomic resolutions on par with those realized in frequency-modulation AFM (FM-AFM) with quartz tuning forks.


Author(s):  
M. Tortonese ◽  
F. J. Giessibl

The atomic force microscope (AFM) works by measuring the deflection of a cantilever as it is scanned over a sample. A sharp tip at the end of the cantilever is responsible for the high lateral resolution achieved with the AFM. There are several ways to measure the deflection of the cantilever. The technique used to measure the deflection of the cantilever most often dictates the mechanical complexity and stability of the instrument. Electron tunneling, interferometry and capacitive sensors have been used successfully. The most common way to measure the cantilever deflection is by means of an optical deflection detector.The piezoresistivc cantilever offers a new way to measure the deflection of the cantilever, with performances comparable to the performances of other deflection detectors, and with the advantage that the sensor is incorporated in the cantilever. This simplifies the design and operation of the microscope In particular, the piezoresistive cantilever facilitates the use and often improves the performances of an AFM when operated in ultra high vacuum (UHV), at low temperature, or when used to image large samples.


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