The next step has been to produce rib waveguides, i.e., one-dimensional guiding structures composed by a thin high-index layer deposited on a low-index substrate. Lithography and plasma etching are standard patterning techniques used in microelectronics to design and inhibitor Y-27632 manufacture complex optical functions on waveguides within a small and compact chip format. The aim of this work was to show the possibility of obtaining sulphide waveguides with good physical properties and low losses using RF-magnetron sputtering for deposition of thin films and dry etching to make rib waveguides. Thus, an optimization of these films and their dry etching will arise from the characterization of their morphological, topographical or optical properties.
The characterization of these optical Inhibitors,Modulators,Libraries waveguides is an essential step for the Inhibitors,Modulators,Libraries proper development of these materials for applications in the optical sensor field.2.?Results and Discussion2.1. Fibre as Useful Tool for Detection2.1.1. Set Up- Detection by infrared fibre evanescent wave spectroscopy (FEWS)Fibre Evanescent Wave Spectroscopy is an efficient Inhibitors,Modulators,Libraries and easy way to record infrared spectra. FEWS enables in situ and in real time studies with no sampling. As represented in Figure 1, the experimental setup consists of a Fourier Transform Infra Red (FTIR) spectrophotometer coupled with a chalcogenide glass fiber and a mercury cadmium tellurium (MCT) detector. The principle of evanescent wave spectroscopy is based on the fact that the light propagates in the optical fiber by total reflections at the interface between the glass and the air.
At each reflection, a part of the energy is absorbed by any chemical or biological species having absorption bands in the IR spectral zones (see Figure 2). Thus, the signal picked up at the fiber output corresponds to the initial signal minus the absorbed Inhibitors,Modulators,Libraries signal giving rise to the spectrum.Figure 1.Schematic representation of the experimental set up used for FEWS experiments. It is composed of an IR source, a chalcogenide glass.Figure 2.Schematic representation Dacomitinib of the experimental set up used for FEWS experiments.The optical fibre sensor used in this study was made of chalcogenide glass from the Te-As-Se (TAS) glass family. This glass is characterized by a high refractive index (around n = 2.8 from 2 to 12 ��m), a large transmission window in the MIR, from 2 to 16 ��m.
Moreover, its thermo-mechanical properties make it easy to shape into optical fibres by pulling a selleck inhibitor glass rod at high temperature (see Section 3.1). To increase the level of detection, a tapered part is created and used as a sensing zone. Typically, the profile in diameter is 400 ��m in the transportation section and 100 ��m in the tapered section. In this experimental configuration, the evanescent wave penetration depth allows probing of only the very first microns of the sample.