Description
It has been several decades since the first laser was assembled by T. Maiman and his research on generation of coherent radiation by the photoexcited ruby was published in 1960 [1]. Several other works, however, prior to his study were also aimed on creation of Light Amplifier by Stimulated Emission of Radiation (LASER). Thus, one can find the description of laser on ammonia capable of amplifying the microwaves, and therefore called MASER, with induced radiation in works by N.G. Basov and A.M. Prohorov in 1958 [2,3] and in works by C.H. Townes and A.L. Schawlow [4]. And even earlier, the possibility of the existence of induced atomic radiation itself was yet foreseen in 1916 by A. Einstein in his work on the theory of interaction of the electromagnetic radiation with matter [5]. The discovery of laser irradiation in 1960 therefore was a logical conclusion of many years theoretical and experimental research and became one of the most meaningful breakthrough in science and technology in XX century.
Since then, the laser technologies have grown to incredible opportunities and applications. Lasers have occupied a significant field in physics and penetrated nearly all scientific areas. Because of their unique properties, laser beams can efficiently serve in medicine as a surgical instrument to perform the tiniest operations [6] and with the same success in industry as a powerful cutter capable of ripping iron sheets of several centimetres thick [7]. Whereas lasers themselves can be effectively used as both diagnostic and research tools their development is still in progress. The requirements to the laser beams as well as the accuracy in controlling the chosen parameters are varying in a wide range of pulse durations and energies depending on their applications. To nowadays in physics and biophysics the pulse duration has shrunk to attoseconds and energies around 1kJ become possible to be reached in a single pulse. At such high power, of 1012 Watt and more, realized upon the absorption of the laser pulse, the matter can undergo a transition to solid dense plasma state that results at least in change of the surface morphology and usually in partial removal of the material (ablation). Especially, the ability of laser beams to serve for a high density energy deposition into a limited area (sub micron scale) and on a very short time scale (less then 10 ps) has been widely exploited in nanostructuring experiments – the process of generation of nanosize features on material surfaces [8].
There is a strong demand for new technologies which can produce 2 and 3-dimensional nanostructures on a wide range of materials [9,10,11,12]. The most common technology of this type is optical lithography. Since the development of this technology, there has been a gradual reduction in the size of the features produced using optical lithographic techniques [13]. This has been achieved mainly by using shorter wavelength of light and it has been predicted that the technology would still be applicable even for feature sizes below 100 nm [14]. The disadvantages are that optical lithography can only be applied to a small range of materials which must have flat surfaces, hence there is a need for the development of new, more broadly applicable nanostructuring technologies based on laser beam technique.