Non-contact atomic force microscope (ncafm) operation in uhv using radiation pressure excitation of cantilever

Date

2016

Author

Uysallı, Yiğit

Metadata

Show full item record

Item Usage Stats

218
views

0
downloads

In this work a new method for excitation of Non-Contact Atomic Force Microscope (NCAFM) cantilevers by means of radiation pressure was developed and applied for NCAFM imaging for the first time in the world. Piezo excitation is the most common method of cantilever excitation in AFM devices. However, it has few drawbacks, sometimes spurious resonance peaks and non-ideal Lorentzian curves can be observed. Radiation pressure has earlier been used for calibration of AFM cantilevers but has never been used for imaging. A fiber optic interferometer with a single 1310 nm laser was used both for measuring the deflection of the cantilever and for the application of a radiation force onto the cantilever at its resonance frequency using a custom NCAFM which operates in p~2x10-10mbar. The laser power was modulated sinusoidally with constant amplitude at the cantilever‘s resonance frequency utilizing a digital Phase Lock Loop (PLL). For 750μW laser power, the force exerted by radiation pressure is calculated to be 5 pN. The nominal stiffness of ncAFM mode cantilevers are ~40N/m, which results in 0.125 pm displacement due to the radiation power. DC and AC laser current is adjusted to control the DC and AC radiation force on the cantilever. The UHV chamber is pumped down to 2.5x10-10 mbar to increase the Q of the cantilever to ~10,000 and hence to enhance oscillation amplitudes to ~1-2nm. The radiation pressure excitation also enabled the measurement of the cantilever stiffness directly which is in the range of 40-60 N/m. The excitation method was applied during NCAFM imaging and for the first time in the world a NCAFM surface topography image utilizing radiation pressure was taken.

Subject Keywords

Optomechanics., Radiation pressure., Non-contact atomic force microscope.

URI

http://etd.lib.metu.edu.tr/upload/12620490/index.pdf
https://hdl.handle.net/11511/25991

Collections

Graduate School of Natural and Applied Sciences, Thesis

Suggestions

OpenMETU
Core

Non-contact atomic force microscope in ultra high vacuum using radiation pressure excitation of cantilever with Fabry-Perot interferometer Karagöz, Ercan; Oral, Ahmet; Department of Physics (2017) In this study Non-Contact Atomic Force Microscope (NC-AFM) imaging was performed by excitation of the cantilever via radiation pressure in a custom Ultra-High Vacuum (UHV) system. Both the excitation of the cantilever and the measurement of the deflection of the cantilever were done by employing a fiber Fabry-Pérot interferometer obtained by a TiO2 coating of the fiber end. This coating allows for a several times higher interference slope. The second normal mode of the cantilever oscillation, along with the...
Status and trends in high performance magnetic imaging using Scanning Probe Microscopy (SPM) Oral, Ahmet (2016-11-30) A novel method for excitation of Atomic Force Microscope(AFM) cantilevers by means of radiation pressure for imaging has been developed for the first time. Piezo excitation is the most common method for cantilever excitation. However, it has quite a few drawbacks like causing spurious resonance peaks and non-ideal Lorentzian curves. The force exerted by the radiation pressure is quite weak but sufficient to excite the cantilever to tens of nanometers for imaging in vacuum, as the Q increases to few thousand...
Comparison of terahertz technologies for detection and identification of explosives Beigang, Rene; Biedron, Sandra G.; Dyjak, Slawomir; Ellrich, Frank; Haakestad, Magnus W.; Huebsch, Daniel; Kartaloglu, Tolga; Ozbay, Ekmel; Ospald, Frank; Palka, Norbert; Puc, Uros; Czerwinska, Elzbieta; Sahin, Asaf B.; Sesek, Aleksander; Trontelj, Janez; Svigelj, Andrej; Altan, Hakan; van Rheenen, Arthur D.; Walczakowski, Michal (2014-05-06) We present results on the comparison of different THz technologies for the detection and identification of a variety of explosives from our laboratory tests that were carried out in the framework of NATO SET-193 “THz technology for stand-off detection of explosives: from laboratory spectroscopy to detection in the field” under the same controlled conditions. Several laser-pumped pulsed broadband THz time-domain spectroscopy (TDS) systems as well as one electronic frequency-modulated continuous wave (FMCW) d...
Installation of the METU Defocusing Beamline to Perform Space Radiation Tests Demirköz, Melahat Bilge; Poyrazoglu, Anil Berkay; Seckin, Caner; Uslu, Pelin; Celik, Nazire; Bulbul, Besna; Albarodi, Abdulrahman; Akcelik, Selen; Orhan, Yusuf; Avaroglu, Akanay; Kilic, Erinc; Saral, Caglar; Duran, Selcen Uzun; Yigitoglu, Merve (2019-01-01) METU Defocusing Beamline (DBL) is being installed at TAEA SANAEM Proton Accelerator Facility [1] for radiation tests of electronic devices to be used in satellites and spacecrafts which are exposed to a high radiation dose in space or at the Hi-Lumi LHC [2]. 15 - 30 MeV protons from the accelerator are spread out over an area of 15.40 X 21.55 cm to provide large irradiation in accordance to ESA/ESCC No. 25100 standard with METU-DBL. A wide selectable flux menu ranging from 10(5) - 10(10) p/cm(2)/s will be a...
Radiation pressure excitation of a low temperature atomic force/magnetic force microscope for imaging in 4-300 K temperature range Celik, Umit L; KARCI, Ozgur; UYSALLI, Yigit; Özer, Hakkı Tunçay; Oral, Ahmet (2017-01-01) We describe a novel radiation pressure based cantilever excitation method for imaging in dynamic mode atomic force microscopy (AFM) for the first time. Piezo-excitation is the most common method for cantilever excitation, however it may cause spurious resonance peaks. Therefore, the direct excitation of the cantilever plays a crucial role in AFM imaging. A fiber optic interferometer with a 1310 nm laser was used both for the excitation of the cantilever at the resonance and the deflection measurement of the...

Citation Formats

Y. Uysallı, “Non-contact atomic force microscope (ncafm) operation in uhv using radiation pressure excitation of cantilever,” M.S. - Master of Science, Middle East Technical University, 2016.