Precise measurement of ac susceptibility

While the principles of the ac susceptibility technique are relatively simple and well understood there are still numerous possible variations in construction of practical susceptometer devices. In many cases the signals are small either due to the reduced sample volume (small single crystals, thin films) or it is small due to intrinsic reasons (like in paramagnets far above their ordering temperature). The design of the sample/sensor core of our susceptometry provides an inherent thermal stability and almost entirely suppressed offset voltage, which enable the unsurpassed sensitivity of our integrated measuring systems: Expressed in equivalent magnetic moment it reaches almost 10-9 EMU

Contact: dr. sc. Mladen Prester

Spectroscopy

We develop spectroscopy diagnostic methods for various types of plasmas such as laser induced plasma, radio frequency inductively or capacity bound plasma or atmospheric plasma. These methods include optical emission spectroscopy (OES), absorption spectroscopy by means of optical resonator (CRDS), laser induces breakdown spectroscopy (LIBS), time-of-flight mass spectroscopy TOF-MS. The applications include modifications of surfaces of materials (polymers, composite materials, metals, paper), deposition of thin films (for producing solar cells), plasma assisted production of nanostructures, detection elements in traces and analyses of composition of materials, laser ignition of discharges and development of plasma light sources. By using mobile miniscule spectrometers, we may perform emission spectroscopy measurements of various processes in laboratory and industry environments in real time.

Contact: dr. sc. Slobodan Milošević

Digital interferometry

Time-averaged holographic interferometry is a known technique frequently used for analyzing vibration properties of objects. The development of array photo-detectors allowing long integration times enabled the capture of time-averaged holograms. A new technique called ‘subtraction digital holography’ has been recently developed for suppressing the zero-order disturbance in off-axis digital holography. In this work, we combine the time-averaged principle with subtraction digital holography technique. Results for a torsional micro-electro-mechanical systems (MEMS) and an oscillating membrane demonstrate clear hologram reconstructions covered with high-contrast fringes that describe the vibration modes.

Contact: dr. sc. Nazif Demoli