Modelling and analysis of fibre microlenses with ray-tracing and finite-difference methods

Fibre optic microlenses are small optical elements formed on the end-faces of optical fibres. Their dimensions range from a few tens to hundreds of micrometres. In the article, four optical fibre microlenses are modelled and analysed. Microlenses are used for light beam manipulation and quantitative metrics are needed to evaluate the results, for example, the size of focusing spot or intensity distribution. All four lenses tested are made of rods of the same refractive index; they were welded to a single-mode fibre. Two modelling methods were used to analyse the lenses: ray-tracing and finite-difference time-domain. The ray-tracing algorithm moves rays from one plane to another and refracts them on the surfaces. Finite-difference time-domain consists of calculating Maxwell’s equations by replacing spatial and temporal derivatives by quotients of finite differences. In this paper, the results of the microlenses analyses obtained from ray-tracing and finite-difference timedomain methods were compared. Both mets of analysis showed the presence of undesirable side lobes related to lens design, namely rods too long for lens fabrication. The test results were compared with the measurements made with the knife-edge method. The use of a single tool to determine parameters of an optical fibre lens does not allow for precise determination of its properties. It is necessary to use different tools and programs. This allows a complete analysis of the beam parameters, letting us find the causes of technical issues that limit the performance of the lenses

Przygotowanie i badanie warstw organicznych dla zastosowań fotowoltaicznych

W artykule przedstawiono proces otrzymywania cienkich warstw organicznych. Nakładanie warstw na podłoża szklane odbywało się metodą spin-coatingu. Podczas procesu modyfikowane były takie parametry, jak: stężenie związku, rodzaj zastosowanego rozpuszczalnika, prędkość wirowania, czas wirowania oraz ilość naniesionej substancji. Zbadano właściwości otrzymanych cienkich warstw organicznych. Pomiaru ich grubości dokonano za pomocą profilometru optycznego, a następnie wynik zweryfikowano na profilometrze mechanicznym. Następnie zmierzono charakterystykę transmitancji na spektrofotometrze. W rezultacie przeprowadzonych prac opracowano technologię nanoszenia 100 nm warstw organicznych na podłoże szklane

Low Temperature Co-fired Ceramics Plasma Generator for Atmospheric Pressure Gas Spectroscopy

AbstractAccurate and reliable measurements of gas composition are very important in science and industry applications. One way to accomplish this task is to measure spectrum of plasma gas discharge. In our work we propose integrated microcell for optical measurements of gas discharge at atmospheric pressure. This device is fabricated using Low Temperature Co-fired Ceramics (LTCC) technology. Investigated gas is excited in buried air-cavity, placed between two electrodes. Discharge is created using high alternating voltage (30kV). Optical signal is then transmitted through an integrated optical fiber to the miniature spectrometer. Because different gases have different emission lines, plot of light intensity vs. wavelength provides information about molecular composition of the investigated gas sample. In this work, design, fabrication and performance of the LTCC- based gas discharge chamber is presented. Spectral measurements are performed for air, argon and nitrogen. Moreover, influence of gas flow rate on obtained emission spectrum is discussed