We report the fabrication of a novel fiber-optic sensor device, based on the use of a microsphere conformally coated with a thin layer of zinc oxide (ZnO) by atomic layer deposition (ALD), and its use as a refractive index sensor. The microsphere was prepared on the tip of a single-mode optical fiber, on which a conformal ZnO thin film of 200 nm was deposited using an ALD process based on diethyl zinc (DEZ) and water at 100 °C. The modified fiber-optic microsphere was examined using scanning electron microscopy and Raman spectroscopy. Theoretical modeling has been carried out to assess the structure performance, and the performed experimental measurements carried out confirmed the enhanced sensing abilities when the microsphere was coated with a ZnO layer. The fabricated refractive index sensor was operating in a reflective mode of a Fabry–Pérot configuration, using a low coherent measurement system. The application of the ALD ZnO coating enabled for a better measurement of the refractive index of samples in the range of the refractive index allowed by the optical fiber. The proof-of-concept results presented in this work open prospects for the sensing community and will promote the use of fiber-optic sensing technologies.

In this work we present the fabrication and characterization of a diamond film which can be utilized in the construction of optical sensors for the investigation of biological samples. We produced a nitrogen-doped diamond (NDD) film using a microwave plasma enhanced chemical vapor deposition (MWPECVD) system. The NDD film was investigated with the use of scanning electron microscopy (SEM), atomic force microscopy (AFM) and Raman spectroscopy. The NDD film was used in the construction of the fiber optic sensor. This sensor is based on the Fabry–Pérot interferometer working in a reflective mode and the NDD film is utilized as a reflective layer of this interferometer. Application of the NDD film allowed us to obtain the sensor of hemoglobin concentration with linear work characteristics with a correlation coefficient (R²) equal to 0.988.

This paper presents a concept of an endomicroscope for an early detection of neoplastic lesions in the human stomach tissue, based on the swept source optical coherence tomography (SS-OCT) and a measurement probe with integrated Mirau micro interferometer. The system consists of pigtailed illumination and detection blocks, connected via a Gradient Index (GRIN) lens collimator to a micro-opto-electro-mechanical systems (MOEMS) measurement probe (4 mm × 4 mm × 20 mm). The technology of Mirau micro interferometer is based on vertical multi-wafer bonding approach. The MOEMS probe is intended to be mounted on a continuum robot arm to perform in vivo microscopy of stomach tissues. First, the optical design of the SS-OCT endomicroscope is described, including an analysis of sensitivity. Then, we focus on the fabrication technologies and optical characterization of a key component of the Mirau micro interferometer, i.e., monolithically integrated focusing glass lens. SS-OCT endomicroscope will provide a fast axial scanning of tissues with A-scan sweep rate of 110 kHz, offering the axial resolution of 5.2 μm and the lateral resolution of 10.2 μm.