Atomic force microscopy (AFM) belongs to the high resolution and high sensitivity surface imaging technologies. In this method force interactions between the tip and the surface are observed to characterize sample properties. In the so-called contact AFM (C AFM) mode the tip is brought into continuous contact with the sample. Significant progress in the AFM technology can be obtained, when the so-called active cantilever technology is implemented in the surface measurements. The built-in deflection actuator enables very precise excitation of the cantilever. Moreover, as the mass of the beam is very small the static beam displacement can be controlled in the wide frequency range. In the experiments, which we describe in this article, we applied the so called active electromagnetic cantilevers. They integrate a conductive loop which, when immersed in the magnetic field and biased with electric current, acts as an electromagnetic deflection actuator. The induced and precisely estimated Lorentz force, which is a function of bias current, cantilever geometry and magnetic field makes the cantilever deflect. Moreover, the probe stiffness can be calibrated with lower uncertainty as in the case of standard thermomechanical analysis. NZ AFM technology required application of a novel control algorithm, called PredPID, in which the cantilever bending caused by a proportional-integral-derivative (PID) block maintaining the constant load force was predicted.

In this paper we present a metrological measurement technique that is a combination of fibre optic interferometry and a microelectromechanical system (MEMS) sensor for photon force (PF) measurement with traceability via an electromagnetic way. The main advantage of the presented method is the reference to the current balance, which is the primary mass/force metrological standard. The MEMS cantilever is a transducer of the photon force to the deflection that can be compensated with the use of the Lorentz force. This movement is measured with the use of the interferometer and does not require any mechanical calibration. Combining the MEMS current balance system with the interferometry is then the unique and fully metrological solution. The resolution of the proposed measurement technique is calculated to be 4 pN//Hz^(0.5) (2% uncertainty). The PF–MEMS used for the investigation is the cantilever with the resolution of 46 fN/Hz0.5, which was calculated from the thermomechanical noise, and is far below the whole system resolution limit. As far as the whole construction is based on the fibre optic system, it does not require any complex adjustment procedure and may work as an optomechanical reference in any metrological laboratory.

We present a method for the quantitative determination of the photon force (PF)—the force generated by the radiation pressure of photons reflected from the surface. We propose an experimental setup integrating innovative microelectromechanical system (MEMS) optimized for the detection of photon force (pfMEMS). An active microcantilever was used as the force detector, while the measurement was conducted in a closed-loop setup with electromagnetic force compensation. In opposition to our previous works, this measurement method provides quantitative not qualitative assessment of PF interaction. Final current-balance setup is suitable for light sources from tens of microwatts to few watts. In our article, we present the results of the performed experiments, in which we measured the PF interactions in the range up to 67.5 pN with resolution of 30 fN in the static measurement.