The achievement was developed within research field: (1) Optodynamic aspects of light-matter interaction and presents an important basis for research activities within other two research fields. During the interaction of a laser pulse with the surface of a solid object, the object always gains momentum. The delivered force impulse is manifested as propulsion. Initially, the motion of the object is composed of elastic waves that carry and redistribute the acquired momentum as they propagate and reflect within the solid. Even though only ablation- and light-pressure-induced mechanical waves are involved in propulsion, they are always accompanied by the ubiquitous thermoelastic waves. We have examined the electrodynamics of laser-pulsed optical manipulation. The experimental verification was performed for two limit examples – the generation of elastic waves in the confined ablation and in the radiation pressure regime. The achievement significantly improves the understanding of the optodynamic mechanisms responsible for the momentum transfer from the laser pulse to the solid object. The results represent an important basis for examination different aspects of optodynamic interactions forming the basis for programme research fields (2) Optodynamics of laser manufacturing and other processes, and (3) Optodynamics of laser medical applications. Moreover, the achievement represents an important milestone in R&D activates related with laser induced mass transfer and laser space propulsion.
COBISS.SI-ID: 13926427
The achievement was developed within research fields: (1) Optodynamic aspects of light-matter interaction and (2) Optodynamics of laser manufacturing and other processes. Within international collaboration with University of Southampton (UK), we have studied the transfer regimes and dynamics of polymer flyers from laser-induced backward transfer (LIBT) via time-resolved shadowgraphy. The experiments were carried out with 150 fs, 800 nm pulses spatially shaped using a digital micromirror device, and laser fluences of up to 3.5 J/cm2 while images were recorded via a CCD camera and a spark discharge lamp. The results contribute to better understanding of the LIBT process, and help to determine experimental parameters for successful LIBT of intact deposits. The achievement importantly contributes to new insights into mechanisms responsible for laser-induced transfer by ultrashort pulses. Additionally, it opens up new possibilities for laser printing that is important in industrial and biomedical applications.
COBISS.SI-ID: 15103003
The achievement was developed within research fields: (1) Optodynamic aspects of light-matter interaction and (2) Optodynamics of laser manufacturing and other processes. Within interdisciplinary collaboration with BTU Cottbus-Senftenberg (Germany) and Institute of Metals and Technology (Slovenia) we studied the laser-induced periodic surface structures (LIPSS) on cold work tool steel by irradiation with a low number of picosecond laser pulses. As expected, the ripples, with a period of about 90% of the laser wavelength, are oriented perpendicular to the laser polarization. Subsequent irradiation with the polarization rotated by 45° or 90° results in a corresponding rotation of the ripples. This is visible already with the first pulse and becomes almost complete - erasing the previous orientation - after as few as three pulses. The phenomenon is not only observed for single-spot irradiation but also for writing long coherent traces. The experimental results strongly defy the role of surface plasmon-polaritons as the predominant key to LIPSS formation and endorse the self-organization model. The achievement importantly clarifies the main mechanisms responsible for LIPSS formation. Additionally, it opens up new approaches for surface functionalization by laser micro/nanostructuring for different applications in fields of photonics, tribology, biomedicine, heat transfer, and corrosion resistance.
COBISS.SI-ID: 14711835
The achievement was developed within research field (3) Optodynamics of laser medical applications. Erbium:yttrium aluminum garnet laser cleaning is a promising technique in endodontic treatment. In our in vitro study, we measured the vapor-bubble dynamics in the root canal by using shadow photography. The canal model was made of a plastic cutout placed between two transparent glass plates. An artificial smear layer was applied to the glass to study cleaning efficiency. In our results, no shock waves have been observed, since the pulp-chamber dimensions have been in the same range as the maximum diameter of the vapor bubble. This leads to the conclusion that shock waves are not the main cleaning mechanism within our model. However, the cleaning effects are also visible in the regions significantly below the bubble. Therefore, it can be concluded that fluid flow induced by the bubble’s oscillations contributes significantly to the canal cleaning. We also proposed a theoretical model for cleaning efficiency and used it to evaluate the measured data. The achievement importantly contributes to new insights into mechanisms of laser cleaning the root canal. Additionally, the results will – in collaboration with Fotona - significantly improve the current laser systems for endodontic treatments.
COBISS.SI-ID: 14461979
The achievement was developed within all three programme research fields. A low-power source, such as a gain-switched laser diode, usually requires several amplification stages to reach sufficient power levels. When operating in burst mode, a correct input burst shape must be determined in order to compensate for gain saturation of all amplifier stages. This achievement develops on closed-form equations that enable saturation compensation in multiamplifier setups, which eliminates the need for an adaptive feedback loop. The theoretical model is evaluated in an experimental setup representing an important basis for further development of laser sources for optodynamic investigations. The achievement significantly contributes to the development of new laser sources for optodynamic investigations within all three research fields of the programme. The results will significantly expand the possibilities for basic and applied research of laser-light-matter interaction.
COBISS.SI-ID: 14072603