The aim of the presented work was to develop a method, which would make possible to identify spectral lines in complicated optical emission spectra. This is an important task for many optical diagnostic methods. It was found out, that the most useful technique combines a manual identification of the lines by the user, according to the developed database of atomic and molecular lines, and an enhanced support of the user by various assistant mechanisms.Therefore, in this work a software for displaying, identification and analysis of the optical emission spectra was developed. Besides the identification, program enables a basic handling of the spectra, corrections of the wavelengths and intensities of the spectra and calculations of some plasma parameters (e. g. calculation of rotational, vibrational and electron temperatures) or other important quantities (e. g. calculation of integrated intensity).The developed software was applied to the study of low pressure RF discharge in neon.PACS : 52.70.Kz

The paper discusses the deposition of protective coatings ranging from organosilicon plasma polymers to SiO 2 -like films and hard diamond-like carbon/silicon oxide (DLC : SiO x ) coatings in radio frequency capacitively coupled discharges using hexamethyldisiloxane (HMDSO). As a result of the optimization of the deposition conditions it was possible to obtain high performance protective coatings. In the HMDSO/O 2 mixture, it was shown that rather than the SiO 2 -like film a hard cross-linked SiO x C y H z polymer film can be used as a protective coating for polycarbonate. The optimum conditions for the deposition of an almost stress-free film were 17% of HMDSO and dc bias voltage of −240 V. The film hardness and elastic modulus were 10 GPa and 75 GPa, respectively. The refractive index at 600 nm was 1.5 and the extinction coefficient decreased from 0.02 at 240 nm down to zero at 600 nm. The films deposited from HMDSO/CH 4 and HMDSO/CH 4 /H 2 mixtures exhibited the attractive properties of DLC films with the partial elimination of some of their drawbacks, such as absorption in the visible and a high intrinsic stress. The optimum concentration of the HMDSO was approximately 21%. Under these conditions the concentration of SiO x in the films was approximately 9 at.%. The film hardness and elastic modulus were above 22 GPa and 120 GPa, respectively.

A passive optical resonator is a special sensor used for measurement of lengths on the nanometer and sub-nanometer scale. Astabilized optical frequency comb can provide an ultimate reference for measuring the wavelength of a tunable laser locked to the optical resonator. If we lock the repetition and offset frequencies of the comb to a high-grade radiofrequency (RF) oscillator its relative frequency stability is transferred from the RF to the optical frequency domain. Experiments in the field of precise length metrology of low-expansion materials are usually of long-term nature so it is required that the optical frequency comb stay in operation for an extended period of time. The optoelectronic closed-loop systems used for stabilization of combs are usually based on traditional analog electronic circuits processing signals from photodetectors. From an experimental point of view, these setups are very complicated and sensitive to ambient conditions, especially in the optical part, therefore maintaining long-time operation is not easy. The research presented in this paper deals with a novel approach based on digital signal processing and a software-defined radio. We describe digital signal processing algorithms intended for keeping the femtosecond optical comb in a long-time stable operation. This need arose during specialized experiments involving measurements of optical frequencies of tunable continuous-wave lasers. The resulting system is capable of keeping the comb in lock for an extensive period of time (8 days or more) with the relative stability better than 1.6 × 10−11.

The progress in the field of optical frequency standards is oriented to femtosecond mode-locked lasers stabilized by technique of the optical frequency synthesis. Such a laser produces a number of coherent frequency components in certain interval of wavelengths. If we control the mode-locked laser by means of i.e. atomic clocks we ensure very stable frequency of these components. With respect to definition of SI unit "one meter" on the basis of speed of light, the stabilized mode-locked laser can be used for implementation of this definition in a non-traditional way. In the work we present our proposal of a system, which converts excellent frequency stability of components generated by the mode-locked laser to a net of discrete absolute lengths represented by a distance of two mirrors of an optical resonator.

We have developed an optical Absolute Distance Meter (ADM) based on the measurement of the phase accumulated by a Radio Frequency wave during its propagation in the air by a laser beam. In this article, the ADM principle will be described and the main results will be presented. In particular, we will emphasize how the choice of an appropriate photodetector can significantly improve the telemeter performances by minimizing the amplitude to phase conversion. Our prototype, tested in the field, has proven its efficiency with a resolution better than 15 μm for a measurement time of 10 ms and distances up to 1.2 km.