The paper presents concept and design of the hemoglobin sensor structure based on integrated optics circuit with grating coupler. The presented integrated optics based sensor structure was designed for determination of the key parameter of the hemoglobin - oxidation level as well as concentration level. The manuscript presents numerical analysis focused on optimization of geometrical properties of selected components of the structure – grating coupler. The analysis were focused on determination of optimal parameters of the grating coupler in particular spatial period Λ and depth of grooves dG. The numerical analysis of the sensor with grating coupler was carried out by Finite Difference Time Domain method (FDTD).
The early diagnosis of cancer is essential since it can be treated more effectively when detected earlier. Visual inspection followed by histological examination is, still today, the gold standard for clinicians. However, a large number of unnecessary surgical procedures are still performed. New diagnostics aids are emerging including the recent techniques of optical coherence tomography (OCT) which permits non-invasive 3D optical biopsies of biological tissues, improving patient’s quality of life. Nevertheless, the existing bulk or fiber optics systems are expensive, only affordable at the hospital and thus, not sufficiently used by physicians or cancer’s specialists as an early diagnosis tool. We developed an endoscopic microsystems based on Mirau interferometry and applied for swept source OCT imaging applied for gastroenterology. The architecture is based on a miniature spectrally tuned a single-channel Mirau interferometer integrated with an electro-thermal MEMS microscanner scanning the sample area.
The paper presents investigation of physical properties of ZnO semiconductor for biomedical applications as a coating layer for example in medical devices and structures. The research was focused on determination of surface topography by SEM method, surface roughness by AFM method, chemical composition by EDS method and crystalline structure of ZnO by Raman spectroscopy. The investigated ZnO coating was deposited by reactive magnetron sputtering on quartz substrate.
The paper presents numerical analysis of integrated optics structure in the form of planar waveguide based on wide band gap oxide semiconductor material. The theoretical analysis of planar waveguide structure was focused on determination of waveguide properties - effective refractive index as a function of waveguide layer thickness for two type of applied waveguide materials – titanium dioxide TiO2 or zinc oxide ZnO and with cover layer based on biological liquid modeled as a saline solution – sodium chloride. The theoretical analysis was carried out for three type of substrate materials: BK7 glass, quartz and sapphire. The second step of research was focused on analysis of homogenous sensitivity dNeff/dnac, finally modal field distribution in planar waveguide structure was also presented.
In this paper, we present the construction and preliminary experimental results of a MOEMS fiber-based integrated probe for endoscopic optical imaging of stomach tissue using a Swept-Source Optical Coherence Tomography (SSOCT). The probe consists of a Mirau micro-interferometer, combined with a GRIN lens collimator and a micromirror scanner. We describe the building blocks of the probe, especially the monolithically integrated Mirau mirointerferometer, fabricated by wafer-level vertical stacking and anodic bonding of Si/glass components, and the electrothermal 2-axis MEMS microscanner allowing large swept angles (up to ±22°) at high frequencies (> kHz) for low driving voltages (<20 V). The results of probe characterization, performed in a designed SS-OCT system, have confirmed proper operation of the probe. The B-scan images were obtained for central wavelength of λc = 840 nm, swept range of Dλ = 60 nm and A-scan frequency of fA= 110 kHz. The axial resolution of the probe is equal to 5.2 μm (determined by applied swept source), whereas the lateral resolution, measured by use of USAF test pattern, is 9.8 μm.
The paper presents numerical analysis of integrated optics structure in the form of planar waveguide based on polymer material (SU-8) with additional cover layer based on wide band gap oxide semiconductor – zinc oxide (ZnO). The theoretical studies of integrated optics structure presented in the paper was focused on determination of waveguide properties such as: modal field distribution and effective refractive index Neff as a function of optical and geometrical properties of waveguide and cover layer. The theoretical studies presented in the paper was carried out for two type of planar waveguide structure: without additional cover layer and with additional cover layer based on ZnO. The second part of the paper presents experimental results focused on technology of a single mode planar waveguide based on SU-8 polymer.
In this paper, we describe the fiber optic low-coherence sensors using thin film. We investigated their metrological parameters. Presented sensors were made with the use of standard telecommunication single mode optical fiber (SMF- 28). Different materials were applied to obtain thick layers, such as boron doped diamond, silver and gold. The thickness of layers used in the experiments ranged from 100 nm to 300 nm. Measurements were performed with broadband source operating at central wavelength 1300 nm. The measurement signal was acquired by an optical spectrum analyzer. Measured signal was analyzed in the spectrum domain. Any change of the phase difference between interfering beams reflected from the sensor head depends on measurand occurred in the spectrum of the measurement signal. We obtain the visibility value of the measured signal equal to 0.97.
The paper presents investigation of physical properties of wide bandgap oxide semiconductor – titanium dioxide for applications in integrated photonics as well as for future applications in gas sensors structures. The investigation presented in the paper was focused on: surface topography of TiO2 layer measured by AFM method, as well as investigation of Raman shift obtained by Raman spectroscopy. Finally the integrated photonics in the form of planar waveguide is also presented.
Optical biosensors have become a powerful alternative to the conventional ways of measurement owing to their great properties, such as high sensitivity, high dynamic range, cost effectiveness and small size. Choice of an optical biosensor's materials is an important factor and impacts the quality of the obtained spectra. Examined biological objects are placed on a cover layer which may react with samples in a chemical, biological and mechanical way, therefore having a negative impact on the measurement reliability. Diamond, a metastable allotrope of carbon with sp3 hybridization, shows outstanding properties such as: great chemical stability, bio-compatibility, high thermal conductivity, wide bandgap and optical transparency. Additionally it possesses great mechanical durability, which makes it a long-lasting material. The protective diamond thin films were deposited on the substrate using Microwave Plasma Assisted Chemical Vapor Deposition (MW PA CVD) system. The surface morphology and roughness was assessed with atomic force microscopy and profilometry. We have performed a series of measurements to assess the biocompatibility of diamond thin films with whole blood. The results show that thin diamond protective layer does not affect the red blood cells, while retaining the sensors high resolution and dynamic range of measurement. Therefore, we conclude that diamond thin films are a viable protective coating for optical biosensors, which allows to examine many biological elements. We project that it can be particularly useful not only for biological objects but also under extreme conditions like radioactive or chemically aggressive environments and high temperatures.
We present applications of titanium dioxide wide bandgap oxide semiconductor and its application in integrated optics devices. The paper is focus on research of physical properties TiO2 such as: spectral transmittance, refractive index, extinction coefficient in the UV-VIS-IR range of light as well as surface topography. In addition we show the numerical calculation and optical characterization of fabricated optical planar waveguide based on TiO2.
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