Related Experiment Video
Updated: May 7, 2026
06:45
Force Spectroscopy of Single Protein Molecules Using an Atomic Force Microscope
Published on: February 28, 2019
Quadrature phase interferometer for high resolution force spectroscopy
Pierdomenico Paolino1, Felipe A Aguilar Sandoval, Ludovic Bellon
1Laboratoire de physique, Université de Lyon, ENS Lyon, CNRS, Lyon 69364, France.
The Review of Scientific Instruments
|October 5, 2013
Summary
We developed a new Atomic Force Microscopy (AFM) deflection sensor using interferometry. This high-resolution setup offers excellent stability and outperforms existing methods for measuring cantilever movement.
Area of Science:
- Physics
- Nanotechnology
- Materials Science
Background:
- Atomic Force Microscopy (AFM) is a powerful tool for nanoscale imaging and manipulation.
- Accurate measurement of cantilever deflection is crucial for AFM performance.
- Existing AFM deflection sensors have limitations in resolution, stability, or dynamic range.
Purpose of the Study:
- To present a novel deflection measurement setup for AFM.
- To achieve high-resolution, stable, and wide-range deflection measurements.
- To demonstrate the setup's performance through thermal noise measurements.
Main Methods:
- Utilizing a quadrature phase differential interferometer.
- Measuring optical path difference between a laser beam reflected from the cantilever tip and a reference beam.
- Designing two configurations: one for low environmental susceptibility and another for calibrated wide spectral range measurements.
Main Results:
- Achieved very high resolution down to 2.5×10(-15) m/√Hz.
- Demonstrated excellent long-term stability and constant sensitivity.
- Exhibited a deflection measurement range up to a few micrometers, outperforming existing literature.
Conclusions:
- The developed AFM deflection measurement setup offers superior performance.
- It provides high precision, stability, and a broad dynamic range.
- This technology has the potential to advance AFM capabilities in various scientific fields.
Related Concept Videos
01:19Mass Analyzers: Common Types
The quadrupole mass analyzer consists of four cylindrical metal rods arranged in a diamond carrying a DC voltage and a radio-frequency AC voltage. The motion of ions through the quadrupole depends on the field strength, causing only ions of a certain m/z to resonate successfully and strike the detector at a given field strength. Though the transmission rate for these analyzers is high, the exact elemental composition of the sample is not determined because of low resolution; however, they are...
01:08Atomic Force Microscopy
Atomic force microscopy (AFM) is a type of scanning probe microscopy that can analyze topographic details of various specimens like ceramics, glass, polymers, and biological samples. AFM offers over 1000 times more resolution than the optical imaging system. Images generated from AFM are three-dimensional surface profiles, offering an advantage over the flat, two-dimensional images from other imaging techniques.
The AFM Probe
The probe is regarded as the heart of any AFM setup and comprises the...
The AFM Probe
The probe is regarded as the heart of any AFM setup and comprises the...
01:15High-Resolution Mass Spectrometry (HRMS)
The resolution of a mass spectrometer depends on the efficiency of separating ions with different ion masses. The mass of an atom is approximated to the sum of the masses of protons and neutrons inside, considering the masses of protons and neutrons as equal. However, the masses of the proton (1.6726 × 10−24 g) and neutron (1.6749 × 10−24 g) are not truly equal. There is a minor error in the expression of atomic masses relative to the simplest atom of hydrogen. For example, the mass of helium...